2024/04/24 更新

写真a

アンサイ サトシ
安齋 賢
Ansai Satoshi
所属
環境生命自然科学学域 教授
職名
教授
ホームページ
外部リンク

学位

  • 博士 (農学) ( 京都大学 )

研究キーワード

  • メダカ

  • ゲノミクス

  • 性的二型

  • 配偶者選好性

  • 種分化

  • ゲノム編集

  • 性染色体

研究分野

  • ライフサイエンス / 遺伝学

  • ライフサイエンス / ゲノム生物学

  • ライフサイエンス / 動物生理化学、生理学、行動学

  • ライフサイエンス / 水圏生命科学

  • ライフサイエンス / 進化生物学

学歴

  • 京都大学   Graduate School of Agriculture   Division of Applied Biosciences

    2013年4月 - 2016年3月

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    国名: 日本国

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  • 京都大学   Graduate School of Agriculture   Division of Applied Biosciences

    2011年4月 - 2013年3月

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    国名: 日本国

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  • 京都大学   Faculty of Agriculture   Division of Bioresource Science

    2007年4月 - 2011年3月

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    国名: 日本国

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経歴

  • 岡山大学   学術研究院 環境生命自然科学学域   教授

    2024年4月 - 現在

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    国名:日本国

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  • 京都大学   大学院農学研究科 ゲノム編集育種講座   特定准教授

    2023年1月 - 2024年3月

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    国名:日本国

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  • 東北大学   大学院生命科学研究科 脳生命統御科学専攻   助教

    2019年11月 - 2022年12月

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  • 基礎生物学研究所   バイオリソース研究室   助教

    2017年11月 - 2019年10月

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  • 日本学術振興会 特別研究員 (PD)

    2016年4月 - 2017年10月

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  • 国立遺伝学研究所   集団遺伝研究系 生態遺伝学研究部門

    2016年4月 - 2017年10月

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  • 日本学術振興会 特別研究員 (DC1)

    2013年4月 - 2016年3月

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▼全件表示

所属学協会

 

論文

  • Repositioning of centromere-associated repeats during karyotype evolution in Oryzias fishes. 査読 国際誌

    Satoshi Ansai, Atsushi Toyoda, Kohta Yoshida, Jun Kitano

    Molecular Ecology   2023年11月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The karyotype, which is the number and shape of chromosomes, is a fundamental characteristic of all eukaryotes. Karyotypic changes play an important role in many aspects of evolutionary processes, including speciation. In organisms with monocentric chromosomes, it was previously thought that chromosome number changes were mainly caused by centric fusions and fissions, whereas chromosome shape changes, that is, changes in arm numbers, were mainly due to pericentric inversions. However, recent genomic and cytogenetic studies have revealed examples of alternative cases, such as tandem fusions and centromere repositioning, found in the karyotypic changes within and between species. Here, we employed comparative genomic approaches to investigate whether centromere repositioning occurred during karyotype evolution in medaka fishes. In the medaka family (Adrianichthyidae), the three phylogenetic groups differed substantially in their karyotypes. The Oryzias latipes species group has larger numbers of chromosome arms than the other groups, with most chromosomes being metacentric. The O. javanicus species group has similar numbers of chromosomes to the O. latipes species group, but smaller arm numbers, with most chromosomes being acrocentric. The O. celebensis species group has fewer chromosomes than the other two groups and several large metacentric chromosomes that were likely formed by chromosomal fusions. By comparing the genome assemblies of O. latipes, O. javanicus, and O. celebensis, we found that repositioning of centromere-associated repeats might be more common than simple pericentric inversion. Our results demonstrated that centromere repositioning may play a more important role in karyotype evolution than previously appreciated.

    DOI: 10.1111/mec.17222

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  • Evolutionary differentiation of androgen receptor is responsible for sexual characteristic development in a teleost fish 査読

    Yukiko Ogino, Satoshi Ansai, Eiji Watanabe, Masaki Yasugi, Yukitoshi Katayama, Hirotaka Sakamoto, Keigo Okamoto, Kataaki Okubo, Yasuhiro Yamamoto, Ikuyo Hara, Touko Yamazaki, Ai Kato, Yasuhiro Kamei, Kiyoshi Naruse, Kohei Ohta, Hajime Ogino, Tatsuya Sakamoto, Shinichi Miyagawa, Tomomi Sato, Gen Yamada, Michael E. Baker, Taisen Iguchi

    Nature Communications   14 ( 1 )   1428 - 1428   2023年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    Abstract

    Teleost fishes exhibit complex sexual characteristics in response to androgens, such as fin enlargement and courtship display. However, the molecular mechanisms underlying their evolutionary acquisition remain largely unknown. To address this question, we analyse medaka (Oryzias latipes) mutants deficient in teleost-specific androgen receptor ohnologs (ara and arb). We discovered that neither ar ohnolog was required for spermatogenesis, whilst they appear to be functionally redundant for the courtship display in males. However, both were required for reproductive success: ara for tooth enlargement and the reproductive behaviour eliciting female receptivity, arb for male-specific fin morphogenesis and sexual motivation. We further showed that differences between the two ar ohnologs in their transcription, cellular localisation of their encoded proteins, and their downstream genetic programmes could be responsible for the phenotypic diversity between the ara and arb mutants. These findings suggest that the ar ohnologs have diverged in two ways: first, through the loss of their roles in spermatogenesis and second, through gene duplication followed by functional differentiation that has likely resolved the pleiotropic roles derived from their ancestral gene. Thus, our results provide insights into how genome duplication impacts the massive diversification of sexual characteristics in the teleost lineage.

    DOI: 10.1038/s41467-023-37026-6

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    その他リンク: https://www.nature.com/articles/s41467-023-37026-6

  • Diversity of sex chromosomes in Sulawesian medaka fishes. 査読 国際誌

    Satoshi Ansai, Javier Montenegro, Kawilarang W A Masengi, Atsushi J Nagano, Kazunori Yamahira, Jun Kitano

    Journal of Evolutionary Biology   35 ( 12 )   1751 - 1764   2022年12月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Recent genetic and genomic studies have revealed tremendous diversity in sex chromosomes across diverse taxa. Closely related species with different sex chromosomes provide us excellent opportunities to investigate the driving forces and the consequences of sex chromosome turnover. In the present study, we investigated the diversity of sex chromosomes of 13 Oryzias species from Sulawesi, Indonesia, which diversified during the last 4.86 million years. Using pooled sequencing, we found sex chromosomes in nine species that all had XY systems, with a species being possibly modified by multiple loci. Seven species (O. woworae, O. asinua, O. wolasi, O. matanensis, O. celebensis, O. hadiatyae, and O. dopingdopingensis) share linkage group (LG) 24 as sex chromosomes; however, they differed in the length and magnitude of sequence divergence between the X and Y chromosomes. The sex chromosome of O. eversi was LG4, which has not been reported as a sex chromosome in any other medaka species. In O. sarasinorum, LG16 and LG22 are associated with sex. Although LG16 was found to be sex-linked in another medaka species previously examined, the sex-determining regions did not overlap. No significant signatures for sex chromosomes were identified in the other four species (O. marmoratus, O. nigrimas, O. nebulosus, and O. orthognathus). Frequent turnovers and the great diversity of the sex chromosomes will make Sulawesian medaka species a model system for investigating the driving forces and consequences of sex chromosome turnover.

    DOI: 10.1111/jeb.14076

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  • Genome editing reveals fitness effects of a gene for sexual dichromatism in Sulawesian fishes. 査読 国際誌

    Satoshi Ansai, Koji Mochida, Shingo Fujimoto, Daniel F Mokodongan, Bayu Kreshna Adhitya Sumarto, Kawilarang W A Masengi, Renny K Hadiaty, Atsushi J Nagano, Atsushi Toyoda, Kiyoshi Naruse, Kazunori Yamahira, Jun Kitano

    Nature Communications   12 ( 1 )   1350 - 1350   2021年3月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Sexual selection drives rapid phenotypic diversification of mating traits. However, we know little about the causative genes underlying divergence in sexually selected traits. Here, we investigate the genetic basis of male mating trait diversification in the medaka fishes (genus Oryzias) from Sulawesi, Indonesia. Using linkage mapping, transcriptome analysis, and genome editing, we identify csf1 as a causative gene for red pectoral fins that are unique to male Oryzias woworae. A cis-regulatory mutation enables androgen-induced expression of csf1 in male fins. csf1-knockout males have reduced red coloration and require longer for mating, suggesting that coloration can contribute to male reproductive success. Contrary to expectations, non-red males are more attractive to a predatory fish than are red males. Our results demonstrate that integrating genomics with genome editing enables us to identify causative genes underlying sexually selected traits and provides a new avenue for testing theories of sexual selection.

    DOI: 10.1038/s41467-021-21697-0

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  • Targeted mutagenesis using CRISPR/Cas system in medaka 査読

    Satoshi Ansai, Masato Kinoshita

    Biology Open   3 ( 5 )   362 - 371   2014年5月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:COMPANY OF BIOLOGISTS LTD  

    Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system-based RNA-guided endonuclease (RGEN) has recently emerged as a simple and efficient tool for targeted genome editing. In this study, we showed successful targeted mutagenesis using RGENs in medaka, Oryzias latipes. Somatic and heritable mutations were induced with high efficiency at the targeted genomic sequence on the DJ-1 gene in embryos that had been injected with the single guide RNA (sgRNA) transcribed by a T7 promoter and capped RNA encoding a Cas9 nuclease. The sgRNAs that were designed for the target genomic sequences without the 5' end of GG required by the T7 promoter induced the targeted mutations. This suggests that the RGEN can target any sequence adjacent to an NGG protospacer adjacent motif (PAM) sequence, which occurs once every 8 bp. The off-target alterations at 2 genomic loci harboring double mismatches in the 18-bp targeting sequences were induced in the RGEN-injected embryos. However, we also found that the off-target effects could be reduced by lower dosages of sgRNA. Taken together, our results suggest that CRISPR/Cas-mediated RGENs may be an efficient and flexible tool for genome editing in medaka.

    DOI: 10.1242/bio.20148177

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  • Efficient targeted mutagenesis in medaka using custom-designed transcription activator-like effector nucleases 査読

    Satoshi Ansai, Tetsushi Sakuma, Takashi Yamamoto, Hiroyoshi Ariga, Norihito Uemura, Ryosuke Takahashi, Masato Kinoshita

    Genetics   193 ( 3 )   739 - 749   2013年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Genetics Society of America  

    Transcription activator-like effector nucleases (TALENs) have become powerful tools for targeted genome editing. Here we demonstrate efficient targeted mutagenesis in medaka (Oryzias latipes), which serves as an excellent vertebrate model for genetics and genomics. We designed and constructed a pair of TALENs targeting the medaka DJ-1 gene, a homolog of human DJ-1 (PARK7). These TALENs induced a number of insertions and deletions in the injected embryos with extremely high efficiency. This induction of mutations occurred in a dose-dependent manner. All screened G0 fish injected with the TALENs transmitted the TALEN-induced mutations to the next generation with high efficiency (44-100%). We also confirmed that these TALENs induced site-specific mutations because none of the mutations were found at potential off-target sites. In addition, the DJ-1 protein was lost in DJ-1Δ7/Δ7 fish that carried a TALEN-induced frameshift mutation in both alleles. We also investigated the effect of the N- and C-terminal regions of the transcription activator-like (TAL) effector domain on the gene-disrupting activity of DJ1-TALENs and found that 287 amino acids at the N terminus and 63 amino acids at the C terminus of the TAL domain exhibited the highest disrupting activity in the injected embryos. Our results suggest that TALENs enable us to rapidly and efficiently establish knockout medaka strains. This is the first report of targeted mutagenesis in medaka using TALENs. The TALEN technology will expand the potential of medaka as a model system for genetics and genomics. © 2013 by the Genetics Society of America.

    DOI: 10.1534/genetics.112.147645

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  • The dwarf neon rainbowfish Melanotaenia praecox, a small spiny-rayed fish with potential as a new Acanthomorpha model fish: II. Establishment of a microinjection procedure for genetic engineering. 査読 国際誌

    Kazuhide Miyamoto, Gembu Abe, Koichi Kawakami, Koji Tamura, Satoshi Ansai

    Developmental Dynamics   2024年2月

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    担当区分:最終著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Rainbowfish is a clade of colorful freshwater fish. Melanotaenia praecox is a small rainbowfish species with biological characteristics that make it potentially useful as an experimental model species. We anticipate that M. praecox could become a new model used in various fields, such as ecology, evolution, and developmental biology. However, few previous studies have described experimental set-ups needed to understand the molecular and genetic mechanisms within this species. RESULTS: We describe detailed procedures for genetic engineering in the rainbowfish M. praecox. By using these procedures, we successfully demonstrated CRISPR/Cas-mediated knockout and Tol2 transposon-mediated transgenesis in this species. Regarding the CRISPR/Cas system, we disrupted the tyrosinase gene and then showed that injected embryos lacked pigmentation over much of their body. We also demonstrated that a Tol2 construct, including a GFP gene driven by a ubiquitous promoter, was efficiently integrated into the genome of M. praecox embryos. CONCLUSIONS: The establishment of procedures for genetic engineering in M. praecox enables investigation of the genetic mechanisms behind a broad range of biological phenomena in this species. Thus, we suggest that M. praecox can be used as a new model species in various experimental biology fields.

    DOI: 10.1002/dvdy.698

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  • Ran-GTP assembles a specialized spindle structure for accurate chromosome segregation in medaka early embryos. 査読 国際誌

    Ai Kiyomitsu, Toshiya Nishimura, Shiang Jyi Hwang, Satoshi Ansai, Masato T Kanemaki, Minoru Tanaka, Tomomi Kiyomitsu

    Nature Communications   15 ( 1 )   981 - 981   2024年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Despite drastic cellular changes during cleavage, a mitotic spindle assembles in each blastomere to accurately segregate duplicated chromosomes. Mechanisms of mitotic spindle assembly have been extensively studied using small somatic cells. However, mechanisms of spindle assembly in large vertebrate embryos remain little understood. Here, we establish functional assay systems in medaka (Oryzias latipes) embryos by combining CRISPR knock-in with auxin-inducible degron technology. Live imaging reveals several unexpected features of microtubule organization and centrosome positioning that achieve rapid, accurate cleavage. Importantly, Ran-GTP assembles a dense microtubule network at the metaphase spindle center that is essential for chromosome segregation in early embryos. This unique spindle structure is remodeled into a typical short, somatic-like spindle after blastula stages, when Ran-GTP becomes dispensable for chromosome segregation. We propose that despite the presence of centrosomes, the chromosome-derived Ran-GTP pathway has essential roles in functional spindle assembly in large, rapidly dividing vertebrate early embryos, similar to acentrosomal spindle assembly in oocytes.

    DOI: 10.1038/s41467-024-45251-w

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  • Behavioral photosensitivity of multi-color-blind medaka: enhanced response under ultraviolet light in the absence of short-wavelength-sensitive opsins. 査読 国際誌

    Kiyono Mizoguchi, Mayu Sato, Rina Saito, Mayu Koshikuni, Mana Sakakibara, Ran Manabe, Yumi Harada, Tamaki Uchikawa, Satoshi Ansai, Yasuhiro Kamei, Kiyoshi Naruse, Shoji Fukamachi

    BMC Neuroscience   24 ( 1 )   67 - 67   2023年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: The behavioral photosensitivity of animals could be quantified via the optomotor response (OMR), for example, and the luminous efficiency function (the range of visible light) should largely rely on the repertoire and expression of light-absorbing proteins in the retina, i.e., the opsins. In fact, the OMR under red light was suppressed in medaka lacking the red (long-wavelength sensitive [LWS]) opsin. RESULTS: We investigated the ultraviolet (UV)- or blue-light sensitivity of medaka lacking the violet (short-wavelength sensitive 1 [SWS1]) and blue (SWS2) opsins. The sws1/sws2 double or sws1/sws2/lws triple mutants were as viable as the wild type. The remaining green (rhodopsin 2 [RH2]) or red opsins were not upregulated. Interestingly, the OMR of the double or triple mutants was equivalent or even increased under UV or blue light (λ = 350, 365, or 450 nm), which demonstrated that the rotating stripes (i.e., changes in luminance) could fully be recognized under UV light using RH2 alone. The OMR test using dichromatic stripes projected onto an RGB display consistently showed that the presence or absence of SWS1 and SWS2 did not affect the equiluminant conditions. CONCLUSIONS: RH2 and LWS, but not SWS1 and SWS2, should predominantly contribute to the postreceptoral processes leading to the OMR or, possibly, to luminance detection in general, as the medium-wavelength-sensitive and LWS cones, but not the SWS cones, are responsible for luminance detection in humans.

    DOI: 10.1186/s12868-023-00835-y

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  • Diversity and Convergence of Sex Determination Mechanisms in Teleost Fish. 招待 査読 国際誌

    Jun Kitano, Satoshi Ansai, Yusuke Takehana, Yoji Yamamoto

    Annual Review of Animal Biosciences   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Sexual reproduction is prevalent across diverse taxa. However, sex-determination mechanisms are so diverse that even closely related species often differ in sex-determination systems. Teleost fish is a taxonomic group with frequent turnovers of sex-determining mechanisms and thus provides us with great opportunities to investigate the molecular and evolutionary mechanisms underlying the turnover of sex-determining systems. Here, we compile recent studies on the diversity of sex-determination mechanisms in fish. We demonstrate that genes in the TGF-β signaling pathway are frequently used for master sex-determining (MSD) genes. MSD genes arise via two main mechanisms, duplication-and-transposition and allelic mutations, with a few exceptions. We also demonstrate that temperature influences sex determination in many fish species, even those with sex chromosomes, with higher temperatures inducing differentiation into males in most cases. Finally, we review theoretical models for the turnover of sex-determining mechanisms and discuss what questions remain elusive. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 12 is February 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

    DOI: 10.1146/annurev-animal-021122-113935

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  • Wnt4a Is Indispensable for Genital Duct Elongation but Not for Gonadal Sex Differentiation in the Medaka, Oryzias latipes. 査読

    Akira Kanamori, Ryota Kitani, Atsuko Oota, Koudai Hirano, Taijun Myosho, Tohru Kobayashi, Kouichi Kawamura, Naoyuki Kato, Satoshi Ansai, Masato Kinoshita

    Zoological Science   40 ( 5 )   348 - 359   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In most vertebrates, the oviducts and sperm ducts are derived from the Müllerian ducts and Wolffian ducts, respectively. However, in teleosts, the genital ducts are formed by the posterior extension of gonads in both sexes. Whether the genital ducts of teleosts are newly evolved organs or variants of Müllerian ducts is an important question for understanding evolutionary mechanisms of morphogenesis. One of the genes essential for Müllerian duct formation in mice is Wnt4, which is expressed in the mesenchyme and induces invagination of the coelomic epithelium and its posterior elongation. Here, we addressed the above question by examining genital duct development in mutants of two Wnt4 genes in the medaka (wnt4a is orthologous to mouse Wnt4, and wnt4b is paralogous). The wnt4b mutants had a short body but were fertile with normal genital ducts. In contrast, both male and female wnt4a mutants had their posterior elongation of the gonads stopped within or just outside the coelom. The mutants retained the posterior parts of ovarian cavities or sperm duct primordia, which are potential target tissues of Wnt4a. The gonads of female scl mutants (unable to synthesize sex steroids) lacked these tissues and did not develop genital ducts. Medaka wnt4a was expressed in the mesenchyme ventral to the genital ducts in both sexes. Taken together, the data strongly suggest that the mouse Müllerian ducts and the medaka genital ducts share homologous developmental processes. Additionally, the wnt4a or wnt4b single mutants and the double mutants did not show sex-reversal, implying that both genes are dispensable for gonadal sex differentiation in the medaka.

    DOI: 10.2108/zs230050

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  • Ghost introgression in ricefishes of the genus Adrianichthys in an ancient Wallacean lake 査読 国際誌

    Kazunori Yamahira, Hirozumi Kobayashi, Ryo Kakioka, Javier Montenegro, Kawilarang W. A. Masengi, Noboru Okuda, Atsushi J. Nagano, Rieko Tanaka, Kiyoshi Naruse, Shoji Tatsumoto, Yasuhiro Go, Satoshi Ansai, Junko Kusumi

    Journal of Evolutionary Biology   36 ( 10 )   1484 - 1493   2023年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley  

    Abstract

    Because speciation might have been promoted by ancient introgression from an extinct lineage, it is important to detect the existence of ‘ghost introgression’ in focal taxa and examine its contribution to their diversification. In this study, we examined possible ghost introgression and its contributions to the diversification of ricefishes of the genus Adrianichthys in Lake Poso, an ancient lake on Sulawesi Island, in which some extinctions are known to have occurred. Population‐genomic analysis revealed that two extant Adrianichthys species, A. oophorus and A. poptae are reproductively isolated from each other. Comparisons of demographic models demonstrated that introgression from a ghost population, which diverged from the common ancestor of A. oophorus and A. poptae, is essential for reconstructing the demographic history of Adrianichthys. The best model estimated that the divergence of the ghost population greatly predated the divergence between A. oophorus and A. poptae, and that the ghost population secondarily contacted the two extant species within Lake Poso more recently. Genome scans and simulations detected a greatly divergent locus, which cannot be explained without ghost introgression. This locus was also completely segregated between A. oophorus and A. poptae. These findings suggest that variants that came from a ghost population have contributed to the divergence between A. oophorus and A. poptae, but the large time‐lag between their divergence and ghost introgression indicates that the contribution of introgression may be restricted.

    DOI: 10.1111/jeb.14223

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  • Multiple colonizations and hybridization of a freshwater fish group on a satellite island of Sulawesi 査読

    Ixchel F. Mandagi, Bayu K. A. Sumarto, Handung Nuryadi, Daniel F. Mokodongan, Sjamsu A. Lawelle, Kawilarang W.A. Masengi, Atsushi J. Nagano, Ryo Kakioka, Jun Kitano, Satoshi Ansai, Junko Kusumi, Kazunori Yamahira

    Molecular Phylogenetics and Evolution   184   107804 - 107804   2023年7月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier {BV}  

    DOI: 10.1016/j.ympev.2023.107804

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  • Optogenetic control of medaka behavior with channelrhodopsin. 査読

    Takahide Seki, Hideaki Takeuchi, Satoshi Ansai

    Development, Growth & Differentiation   65 ( 6 )   288 - 299   2023年6月

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    担当区分:最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Optogenetics enables the manipulation of neural activity with high spatiotemporal resolution in genetically defined neurons. The method is widely used in various model animals in the neuroscience and physiology fields. Channelrhodopsins are robust tools for optogenetic manipulation, but they have not yet been used for studies in medaka. In the present study, we used the CRISPR/Cas9-mediated knock-in approach to establish a transgenic medaka strain expressing the Chloromonas oogama channelrhodopsin (CoChR) in the ISL LIM homeobox 1 (isl1) locus. We demonstrated that light stimuli elicited specific behavioral responses such as bending or turning locomotion in the embryos and pectoral fin movements in the larvae and adults. The response probabilities and intensities of these movements could be controlled by adjusting the intensity, duration, or wavelength of each light stimulus. Furthermore, we demonstrated that the pectoral fin movements in the adult stage could be elicited using a laser pointer to irradiate region including the caudal hind brain and the rostral spinal cord. Our results indicate that CoChR allows for manipulation of medaka behaviors by activating targeted neurons, which will further our understanding of the detailed neural mechanisms of motor control or social behaviors in medaka. This article is protected by copyright. All rights reserved.

    DOI: 10.1111/dgd.12872

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  • Spatio-temporal control of targeted gene expression in combination with CRISPR/Cas and Tet-On systems in Medaka. 査読 国際誌

    Daichi Kayo, Sayaka Kimura, Touko Yamazaki, Kiyoshi Naruse, Hideaki Takeuchi, Satoshi Ansai

    Genesis (New York, N.Y. : 2000)   e23519   2023年5月

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    担当区分:最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Spatial and temporal control of transgene expression is a powerful approach to understand gene functions in specific cells and tissues. The Tet-On system is a robust tool for controlling transgene expression spatially and temporally; however, few studies have examined whether this system can be applied to postembryonic stages of Medaka (Oryzias latipes) or other fishes. Here, we first improved a basal promoter sequence on the donor vector for a nonhomologous end joining (NHEJ)-based knock-in (KI) system. Next, using transgenic Medaka for establishing the Tet-On system by KI, we demonstrated that doxycycline administration for four or more days by feeding can be a stable and efficient method to achieve expression of the transduced reporter gene in adult fish. From these analyses, we propose an optimized approach for a spatio-temporal gene-expression system in the adult stage of Medaka and other small fishes.

    DOI: 10.1002/dvg.23519

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  • CT Image-Based Biopsy to Aid Prediction of HOPX Expression Status and Prognosis for Non-Small Cell Lung Cancer Patients. 査読 国際誌

    Yu Jin, Hidetaka Arimura, YunHao Cui, Takumi Kodama, Shinichi Mizuno, Satoshi Ansai

    Cancers   15 ( 8 )   2023年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This study aimed to elucidate a computed tomography (CT) image-based biopsy with a radiogenomic signature to predict homeodomain-only protein homeobox (HOPX) gene expression status and prognosis in patients with non-small cell lung cancer (NSCLC). Patients were labeled as HOPX-negative or positive based on HOPX expression and were separated into training (n = 92) and testing (n = 24) datasets. In correlation analysis between genes and image features extracted by Pyradiomics for 116 patients, eight significant features associated with HOPX expression were selected as radiogenomic signature candidates from the 1218 image features. The final signature was constructed from eight candidates using the least absolute shrinkage and selection operator. An imaging biopsy model with radiogenomic signature was built by a stacking ensemble learning model to predict HOPX expression status and prognosis. The model exhibited predictive power for HOPX expression with an area under the receiver operating characteristic curve of 0.873 and prognostic power in Kaplan-Meier curves (p = 0.0066) in the test dataset. This study's findings implied that the CT image-based biopsy with a radiogenomic signature could aid physicians in predicting HOPX expression status and prognosis in NSCLC.

    DOI: 10.3390/cancers15082220

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  • A cryptic sex-linked locus revealed by the elimination of a master sex-determining locus in medaka fish 査読

    Jun Kitano, Satoshi Ansai, Shingo Fujimoto, Ryo Kakioka, Mana Sato, Ixchel F. Mandagi, Bayu K.A. Sumarto, Kazunori Yamahira

    The American Naturalist   202 ( 2 )   231 - 240   2023年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:University of Chicago Press  

    DOI: 10.1086/724840

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  • Genome Editing of Medaka. 国際誌

    Rie Hara, Satoshi Ansai, Masato Kinoshita

    Methods in Molecular Biology (Clifton, N.J.)   2637   325 - 339   2023年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Medaka (Oryzias latipes), along with zebrafish (Danio rerio), is a useful experimental model fish. Here, we describe a simple method for generating medaka gene knockout strains using an automated microchip electrophoresis system. We also describe a method for targeted gene knockin using a plasmid carrying a sequence that does not cause off-target effects in medaka. Additionally, knockin method without plasmid cloning is described.

    DOI: 10.1007/978-1-0716-3016-7_25

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  • Mating experiences with the same partner enhanced mating activities of naïve male medaka fish. 査読 国際誌

    Masahiro Daimon, Takafumi Katsumura, Hirotaka Sakamoto, Satoshi Ansai, Hideaki Takeuchi

    Scientific Reports   12 ( 1 )   19665 - 19665   2022年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Mating experience shapes male mating behavior across species, from insects, fish, and birds, to rodents. Here, we investigated the effect of multiple mating experiences on male mating behavior in "naïve" (defined as sexually inexperienced) male medaka fish. The latency to mate with the same female partner significantly decreased after the second encounter, whereas when the partner was changed, the latency to mate was not decreased. These findings suggest that mating experiences enhanced the mating activity of naïve males for the familiar female, but not for an unfamiliar female. In contrast, the mating experiences of "experienced" (defined as those having mated > 7 times) males with the same partner did not influence their latency to mate. Furthermore, we identified 10 highly and differentially expressed genes in the brains of the naïve males after the mating experience and revealed 3 genes that are required for a functional cascade of the thyroid hormone system. Together, these findings suggest that the mating experience of naïve male medaka fish influences their mating behaviors, with neural changes triggered by thyroid hormone activation in the brain.

    DOI: 10.1038/s41598-022-23871-w

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  • Retinal Cone Mosaic in sws1-Mutant Medaka (Oryzias latipes), A Teleost. 査読 国際誌

    Megumi Matsuo, Makoto Matsuyama, Tomoe Kobayashi, Shinji Kanda, Satoshi Ansai, Taichi Kawakami, Erika Hosokawa, Yutaka Daido, Takehiro G Kusakabe, Kiyoshi Naruse, Shoji Fukamachi

    Investigative Ophthalmology & Visual Science   63 ( 11 )   21 - 21   2022年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: Ablation of short single cones (SSCs) expressing short-wavelength-sensitive opsin (SWS1) is well analyzed in the field of regenerative retinal cells. In contrast with ablation studies, the phenomena caused by the complete deletion of SWS1 are less well-understood. To assess the effects of SWS1 deficiency on retinal structure, we established and analyzed sws1-mutant medaka. METHODS: To visualize SWS1, a monoclonal anti-SWS1 antibody and transgenic reporter fish (Tg(sws1:mem-egfp)) were generated. We also developed a CRISPR/Cas-driven sws1-mutant line. Retinal structure of sws1 mutant was visualized using anti-SWS1, 1D4, and ZPR1 antibodies and coumarin derivatives and compared with wild type, Tg(sws1:mem-egfp), and another opsin (lws) mutant. RESULTS: Our rat monoclonal antibody specifically recognized medaka SWS1. Sws1 mutant retained regularly arranged cone mosaic as lws mutant and its SSCs had neither SWS1 nor long wavelength sensitive opsin. Depletion of sws1 did not affect the expression of long wavelength sensitive opsin, and vice versa. ZPR1 antibody recognized arrestin spread throughout double cones and long single cones in wild-type, transgenic, and sws1-mutant lines. CONCLUSIONS: Comparative observation of sws1-mutant and wild-type retinas revealed that ZPR1 negativity is not a marker for SSCs with SWS1, but SSCs themselves. Loss of functional sws1 did not cause retinal degeneration, indicating that sws1 is not essential for cone mosaic development in medaka. Our two fish lines, one with visualized SWS1 and the other lacking functional SWS1, offer an opportunity to study neural network synapsing with SSCs and to clarify the role of SWS1 in vision.

    DOI: 10.1167/iovs.63.11.21

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  • Speciation and adaptation research meets genome editing. 招待 査読 国際誌

    Satoshi Ansai, Jun Kitano

    Philosophical Transactions of the Royal Society of London. Series B, Biological sciences   377 ( 1855 )   20200516 - 20200516   2022年7月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Understanding the genetic basis of reproductive isolation and adaptive traits in natural populations is one of the fundamental goals in evolutionary biology. Genome editing technologies based on CRISPR-Cas systems and site-specific recombinases have enabled us to modify a targeted genomic region as desired and thus to conduct functional analyses of target loci, genes and mutations even in non-conventional model organisms. Here, we review the technical properties of genome editing techniques by classifying them into the following applications: targeted gene knock-out for investigating causative gene functions, targeted gene knock-in of marker genes for visualizing expression patterns and protein functions, precise gene replacement for identifying causative alleles and mutations, and targeted chromosomal rearrangement for investigating the functional roles of chromosomal structural variations. We describe examples of their application to demonstrate functional analysis of naturally occurring genetic variations and discuss how these technologies can be applied to speciation and adaptation research. This article is part of the theme issue 'Genetic basis of adaptation and speciation: from loci to causative mutations'.

    DOI: 10.1098/rstb.2020.0516

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  • Genetic basis for the evolution of pelvic-fin brooding, a new mode of reproduction, in a Sulawesian fish. 査読 国際誌

    Javier Montenegro, Shingo Fujimoto, Satoshi Ansai, Atsushi J Nagano, Masahiro Sato, Yusuke Maeda, Rieko Tanaka, Kawilarang W A Masengi, Ryosuke Kimura, Jun Kitano, Kazunori Yamahira

    Molecular Ecology   31 ( 14 )   3798 - 3811   2022年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Modes of reproduction in animals are diverse, with different modes having evolved independently in multiple lineages across a variety of taxa. However, an understanding of the genomic change driving the transition between different modes of reproduction is limited. Several ricefishes (Adrianichthyidae) on the island of Sulawesi have a unique mode of reproduction called "pelvic-fin brooding," wherein females carry externally fertilized eggs until hatching using their pelvic fins. Phylogenomic analysis demonstrated pelvic-fin brooders to have evolved at least twice in two distant clades of the Adrianichthyidae. We investigated the genetic architecture of the evolution of this unique mode of reproduction. Morphological analyses and laboratory observations revealed that females of pelvic-fin brooders have longer pelvic fins and a deeper abdominal concavity, and that they can carry an egg clutch for longer than non-brooding adrianichthyids, suggesting that these traits play important roles in this reproductive mode. Quantitative trait locus mapping using a cross between a pelvic-fin brooder Oryzias eversi and a non-brooding O. dopingdopingensis reveals different traits involved in pelvic-fin brooding to be controlled by different loci on different chromosomes. Genomic analyses of admixture detected no signatures of introgression between two lineages with pelvic-fin brooders, indicating that introgression is unlikely to be responsible for repeated evolution of pelvic-fin brooding. These findings suggest that multiple independent mutations may have contributed to the convergent evolution of this novel mode of reproduction.

    DOI: 10.1111/mec.16555

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  • Development of a screening system for agents that modulate taste receptor expression with the CRISPR-Cas9 system in medaka. 査読 国際誌

    Kana Beppu, Rie Tsutsumi, Satoshi Ansai, Nana Ochiai, Mai Terakawa, Marie Mori, Masashi Kuroda, Kazuki Horikawa, Takumi Tomoi, Joe Sakamoto, Yasuhiro Kamei, Kiyoshi Naruse, Hiroshi Sakaue

    Biochemical and Biophysical Research Communications   601   65 - 72   2022年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Taste recognition mediated by taste receptors is critical for the survival of animals in nature and is an important determinant of nutritional status and quality of life in humans. However, many factors including aging, diabetes, zinc deficiency, infection with influenza or cold viruses, and chemotherapy can trigger dysgeusia, for which a standard treatment has not been established. We here established an engineered strain of medaka (Oryzias latipes) that expresses green fluorescent protein (GFP) from the endogenous taste 1 receptor 3 (T1R3) gene locus with the use of the CRISPR-Cas9 system. This T1R3-GFP knock-in (KI) strain allows direct visualization of expression from this locus by monitoring of GFP fluorescence. The pattern of GFP expression in the T1R3-GFP KI fish thus mimicked that of endogenous T1R3 gene expression. Furthermore, exposure of T1R3-GFP KI medaka to water containing monosodium glutamate or the anticancer agent 5-fluorouracil resulted in an increase or decrease, respectively, in GFP fluorescence intensity, effects that also recapitulated those on T1R3 mRNA abundance. Finally, screening for agents that affect GFP fluorescence intensity in T1R3-GFP KI medaka identified tryptophan as an amino acid that increases T1R3 gene expression. The establishment of this screening system for taste receptor expression in medaka provides a new tool for the development of potential therapeutic agents for dysgeusia.

    DOI: 10.1016/j.bbrc.2022.02.082

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  • Diversity of lateral line patterns and neuromast numbers in the genus Oryzias. 査読 国際誌

    Ali Seleit, Satoshi Ansai, Kazunori Yamahira, Kawilarang W A Masengi, Kiyoshi Naruse, Lázaro Centanin

    The Journal of Experimental Biology   224 ( 24 )   2021年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A remarkable diversity of lateral line patterns exists in adult teleost fishes, the basis of which is largely unknown. By analysing the lateral line patterns and organ numbers in 29 Oryzias species and strains we report a rapid diversification of the lateral line system within this genus. We show a strong dependence of lateral line elaboration (number of neuromasts per cluster, number of parallel lateral lines) on adult species body size irrespective of phylogenetic relationships. In addition, we report that the degree of elaboration of the anterior lateral line, posterior lateral line and caudal neuromast clusters is tightly linked within species, arguing for a globally coordinated mechanism controlling lateral line organ numbers and patterns. We provide evidence for a polygenic control over neuromast numbers and positioning in the genus Oryzias. Our data also indicate that the diversity in lateral lines can arise as a result of differences in patterning both during embryonic development and post-embryonically, where simpler embryonic patterns generate less complex adult patterns and organ numbers, arguing for a linkage between the two processes.

    DOI: 10.1242/jeb.242490

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  • Myosin phosphatase target subunit 1governs integrity of the embryonic gut epithelium to circumvent atresia development in medaka,Oryzias latipes

    Daisuke Kobayashi, Kazuhiko Matsuo, Tetsuaki Kimura, Satoshi Ansai, Hayato Yokoi, Shigeo Takashima, Tadao Kitagawa, Takahiro Kage, Takanori Narita, Tomoko Jindo, Masato Kinoshita, Kiyoshi Naruse, Yoshiro Nakajima, Masaki Shigeta, Shinichiro Sakaki, Satoshi Inoue, Rie Saba, Kei Yamada, Takahiko Yokoyama, Yuji Ishikawa, Kazuo Araki, Yumiko Saga, Hiroyuki Takeda, Kenta Yashiro

    2021年12月

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    出版者・発行元:Cold Spring Harbor Laboratory  

    Abstract

    Background

    Intestinal atresia (IA) is a congenital gut obstruction caused by the absence of gut opening. Genetic factors are assumed to be critical for the development of IA, in addition to accidental vascular insufficiency or mechanical strangulation. However, the molecular mechanism underlying IA remains poorly understood.

    Results

    In this study, to better understand such a mechanism, we isolated a mutant ofOryzias latipes(the Japanese rice fish known as medaka) generated by N-ethyl-N-nitrosourea mutagenesis, in which IA develops during embryogenesis. Positional cloning identified a nonsense mutation in themyosin phosphatase target subunit 1(mypt1) gene. Consistent with known Mypt1 function, the active form of myosin regulatory light chain (MRLC), which is essential for actomyosin contraction, and F-actin were ectopically accumulated in the intestinal epithelium of mutant embryos, whereas cell motility, proliferation and cell death were not substantially affected. Corresponding to the accumulation site of F-actin/active MRLC, the intestinal epithelium architecture was disordered. Importantly, blebbistatin, a non-muscle myosin inhibitor, attenuated the development of IA in the mutant.

    Conclusions

    Cytoskeletal contraction governed bymypt1regulates the integrity of the embryonic intestinal epithelium. This study provides new insight into our understanding of the mechanism of IA development in humans.

    Bullet Points

    Medakamypt1mutants display intestinal atresia.

    The level of phosphorylated myosin regulatory light chain was higher inmypt1mutant embryos than inwild-typeembryos.

    The levels of F-actin appeared elevated in the intestinal epithelium ofmypt1mutants.

    Blebbistatin, an inhibitor of non-muscle myosin II, rescued intestinal atresia inmypt1mutant embryos.

    DOI: 10.1101/2021.12.10.472183

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  • Species divergence and repeated ancient hybridization in a Sulawesian lake system. 査読 国際誌

    Ixchel F Mandagi, Ryo Kakioka, Javier Montenegro, Hirozumi Kobayashi, Kawilarang W A Masengi, Nobuyuki Inomata, Atsushi J Nagano, Atsushi Toyoda, Satoshi Ansai, Masatoshi Matsunami, Ryosuke Kimura, Jun Kitano, Junko Kusumi, Kazunori Yamahira

    Journal of Evolutionary Biology   34 ( 11 )   1767 - 1780   2021年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    An increasing volume of empirical studies demonstrated that hybridization between distant lineages may have promoted speciation in various taxa. However, the timing, extent and direction of introgressive hybridization remain unknown in many cases. Here, we report a possible case in which repeated hybridization promoted divergence of Oryzias ricefishes (Adrianichthyidae) on Sulawesi, an island of Wallacea. Four Oryzias species are endemic to the Malili Lake system in central Sulawesi, which is composed of five tectonic lakes; of these, one lake is inhabited by two species. Morphological and population genomic analyses of genome-wide single-nucleotide polymorphisms revealed that these two sympatric species are phylogenetically sister to but substantially reproductively isolated from each other. Analyses of admixture and comparison of demographic models revealed that the two sympatric species experienced several substantial introgressions from outgroup populations that probably occurred soon after they had secondary contact with each other in the lake. However, the ratio of migrants from the outgroups was estimated to be different between the two species, which is consistent with the hypothesis that these introgressions aided their divergence or prevented them from forming a hybrid swarm. Repeated lake fragmentations and fusions may have promoted diversification of this freshwater fish species complex that is endemic to this ancient lake system.

    DOI: 10.1111/jeb.13932

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  • A modified Tet-ON system minimizing leaky expression for cell-type specific gene induction in medaka fish. 査読

    Osamu Hosoya, Myung Chung, Satoshi Ansai, Hideaki Takeuchi, Mary Miyaji

    Development, Growth & Differentiation   2021年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The Tet-ON system is an important molecular tool for temporally and spatially-controlled inducible gene expression. Here, we developed a Tet-ON system to induce transgene expression specifically in the rod photoreceptors of medaka fish. Our modified reverse tetracycline-controlled transcriptional transactivator (rtTAm) with 5 amino acid substitutions dramatically improved the leakiness of the transgene in medaka fish. We generated a transgenic line carrying a self-reporting vector with the rtTAm gene driven by the Xenopus rhodopsin promoter and a tetracycline response element (TRE) followed by the green fluorescent protein (GFP) gene. We demonstrated that GFP fluorescence was restricted to the rod photoreceptors in the presence of doxycycline in larval fish (9 days post-fertilization). The GFP fluorescence intensity was enhanced with longer durations of doxycycline treatment up to 72 h and in a dose-dependent manner (5-45 μg/ml). These findings demonstrate that the Tet-ON system using rtTAm allows for spatiotemporal control of transgene expression, at least in the rod photoreceptors, in medaka fish.

    DOI: 10.1111/dgd.12743

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  • Mesozoic origin and 'out-of-India' radiation of ricefishes (Adrianichthyidae). 査読 国際誌

    Kazunori Yamahira, Satoshi Ansai, Ryo Kakioka, Hajime Yaguchi, Takeshi Kon, Javier Montenegro, Hirozumi Kobayashi, Shingo Fujimoto, Ryosuke Kimura, Yusuke Takehana, Davin H E Setiamarga, Yasuoki Takami, Rieko Tanaka, Ken Maeda, Hau D Tran, Noriyuki Koizumi, Shinsuke Morioka, Vongvichith Bounsong, Katsutoshi Watanabe, Prachya Musikasinthorn, Sein Tun, L K C Yun, Kawilarang W A Masengi, V K Anoop, Rajeev Raghavan, Jun Kitano

    Biology Letters   17 ( 8 )   20210212 - 20210212   2021年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The Indian subcontinent has an origin geologically different from Eurasia, but many terrestrial animal and plant species on it have congeneric or sister species in other parts of Asia, especially in the Southeast. This faunal and floral similarity between India and Southeast Asia is explained by either of the two biogeographic scenarios, 'into-India' or 'out-of-India'. Phylogenies based on complete mitochondrial genomes and five nuclear genes were undertaken for ricefishes (Adrianichthyidae) to examine which of these two biogeographic scenarios fits better. We found that Oryzias setnai, the only adrianichthyid distributed in and endemic to the Western Ghats, a mountain range running parallel to the western coast of the Indian subcontinent, is sister to all other adrianichthyids from eastern India and Southeast-East Asia. Divergence time estimates and ancestral area reconstructions reveal that this western Indian species diverged in the late Mesozoic during the northward drift of the Indian subcontinent. These findings indicate that adrianichthyids dispersed eastward 'out-of-India' after the collision of the Indian subcontinent with Eurasia, and subsequently diversified in Southeast-East Asia. A review of geographic distributions of 'out-of-India' taxa reveals that they may have largely fuelled or modified the biodiversity of Eurasia.

    DOI: 10.1098/rsbl.2021.0212

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  • Resource partitioning is not coupled with assortative mating in sympatrically divergent ricefish in a Wallacean ancient lake. 査読 国際誌

    Ryo Kakioka, Nobu Sutra, Hirozumi Kobayashi, Satoshi Ansai, Kawilarang W A Masengi, Atsushi J Nagano, Noboru Okuda, Rieko Tanaka, Masahiro Sato, Kazunori Yamahira

    Journal of Evolutionary Biology   34 ( 7 )   1133 - 1143   2021年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Sympatric speciation is considered to be difficult without the coupling between ecological traits that allow resource partitioning and reproductive traits that allow assortative mating. Such "magic traits" are known to be involved in most of the compelling examples of sympatric speciation. In this study, we report a possible case of sympatric speciation without magic traits. Three species of ricefish (genus Oryzias) are suggested to have diverged sympatrically within Lake Poso, an ancient lake in Sulawesi. An analysis of genome-wide single-nucleotide polymorphisms showed that these three species are reproductively isolated from each other throughout the lake. Stable isotope analyses revealed that the three species use different food resources, which reflect differences in their feeding morphologies (gill rakers and digestive tracts) and feeding sites. Field and laboratory observations showed that O. nebulosus and O. orthognathus share a mating habitat of cobbles, where they scatter fertilized eggs, whereas this site is never used by O. nigrimas, indicating that assortative mating is partly achieved by spatial isolation. The small, less-adhesive eggs of O. nebulosus and O. orthognathus probably reflect their adaptation to spawning on cobble beaches. Laboratory mating experiments showed strong prezygotic isolation between O. nebulosus and O. orthognathus, which is achieved by strong species recognition presumably by both sexes based on species-specific mating dances and nuptial coloration. In summary, the assortative mating of O. nebulosus and O. orthognathus is probably not coupled to resource partitioning. We discussed how sympatric speciation among these species might have been achieved even without magic traits.

    DOI: 10.1111/jeb.13874

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  • Genetic basis for variation in the number of cephalic pores in a hybrid zone between closely related species of goby, Gymnogobius breunigii and Gymnogobius castaneus 査読

    Ryo Kakioka, Manabu Kume, Asano Ishikawa, Satoshi Ansai, Takuya K Hosoki, Yo Y Yamasaki, Atsushi J Nagano, Atsushi Toyoda, Jun Kitano

    Biological Journal of the Linnean Society   133 ( 1 )   143 - 154   2021年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Oxford University Press (OUP)  

    <title>Abstract</title>
    Populations or species exploiting different habitats can differ in sensory perception as a result of divergent adaptation. In bony fish, the water current is perceived via neuromasts, the end organ of the lateral line system. Although fish in different habitats are known to vary in neuromasts, we know little about the genetic basis for such variation. Here, we investigate the genetic basis for variation in supraorbital neuromasts in a hybrid zone between the Japanese gobies Gymnogobius breunigii and Gymnogobius castaneus. The former has supraorbital canal neuromasts with six cephalic pores, whereas the latter has only superficial neuromasts with no canals or pores in the supraorbital region. Our genomic analysis showed that G. breunigii and G. castaneus occur mainly in the lower and mid/upper reaches, respectively. In a river in northern Japan, hybrids were found at the sites between the habitats of the two species. These hybrids exhibited anomalies of cephalic pores. Using this hybrid zone, we conducted genome-wide association studies and identified one locus significantly associated with the number of pores. Genomic cline analysis in the hybrid zone demonstrated that this locus exhibited a higher introgression rate compared with the genomic background, indicating the possibility of adaptive introgression.

    DOI: 10.1093/biolinnean/blab033

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  • Genome Sequence of the Euryhaline Javafish Medaka, Oryzias javanicus: A Small Aquarium Fish Model for Studies on Adaptation to Salinity. 査読 国際誌

    Yusuke Takehana, Margot Zahm, Cédric Cabau, Christophe Klopp, Céline Roques, Olivier Bouchez, Cécile Donnadieu, Celia Barrachina, Laurent Journot, Mari Kawaguchi, Shigeki Yasumasu, Satoshi Ansai, Kiyoshi Naruse, Koji Inoue, Chuya Shinzato, Manfred Schartl, Yann Guiguen, Amaury Herpin

    G3 (Bethesda, Md.)   10 ( 3 )   907 - 915   2020年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The genus Oryzias consists of 35 medaka-fish species each exhibiting various ecological, morphological and physiological peculiarities and adaptations. Beyond of being a comprehensive phylogenetic group for studying intra-genus evolution of several traits like sex determination, behavior, morphology or adaptation through comparative genomic approaches, all medaka species share many advantages of experimental model organisms including small size and short generation time, transparent embryos and genome editing tools for reverse and forward genetic studies. The Java medaka, Oryzias javanicus, is one of the two species of medaka perfectly adapted for living in brackish/sea-waters. Being an important component of the mangrove ecosystem, O. javanicus is also used as a valuable marine test-fish for ecotoxicology studies. Here, we sequenced and assembled the whole genome of O. javanicus, and anticipate this resource will be catalytic for a wide range of comparative genomic, phylogenetic and functional studies. Complementary sequencing approaches including long-read technology and data integration with a genetic map allowed the final assembly of 908 Mbp of the O. javanicus genome. Further analyses estimate that the O. javanicus genome contains 33% of repeat sequences and has a heterozygosity of 0.96%. The achieved draft assembly contains 525 scaffolds with a total length of 809.7 Mbp, a N50 of 6,3 Mbp and a L50 of 37 scaffolds. We identified 21454 predicted transcripts for a total transcriptome size of 57, 146, 583 bps. We provide here a high-quality chromosome scale draft genome assembly of the euryhaline Javafish medaka (321 scaffolds anchored on 24 chromosomes (representing 97.7% of the total bases)), and give emphasis on the evolutionary adaptation to salinity.

    DOI: 10.1534/g3.119.400725

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  • Sexually dimorphic role of oxytocin in medaka mate choice. 査読 国際誌

    Saori Yokoi, Kiyoshi Naruse, Yasuhiro Kamei, Satoshi Ansai, Masato Kinoshita, Mari Mito, Shintaro Iwasaki, Shuntaro Inoue, Teruhiro Okuyama, Shinichi Nakagawa, Larry J Young, Hideaki Takeuchi

    Proceedings of the National Academy of Sciences of the United States of America   117 ( 9 )   4802 - 4808   2020年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Oxytocin is a central neuromodulator required for facilitating mate preferences for familiar individuals in a monogamous rodent (prairie vole), irrespective of sex. While the role of oxytocin in mate choice is only understood in a few monogamous species, its function in nonmonogamous species, comprising the vast majority of vertebrate species, remains unclear. To address this issue, we evaluated the involvement of an oxytocin homolog (isotocin, referred herein as oxt) in mate choice in medaka fish (Oryzias latipes). Female medaka prefer to choose familiar mates, whereas male medaka court indiscriminately, irrespective of familiarity. We generated mutants of the oxt ligand (oxt) and receptor genes (oxtr1 and oxtr2) and revealed that the oxt-oxtr1 signaling pathway was essential for eliciting female mate preference for familiar males. This pathway was also required for unrestricted and indiscriminate mating strategy in males. That is, either oxt or oxtr1 mutation in males decreased the number of courtship displays toward novel females, but not toward familiar females. Further, males with these mutations exhibited enhanced mate-guarding behaviors toward familiar females, but not toward novel females. In addition, RNA-sequencing (seq) analysis revealed that the transcription of genes involved in gamma-amino butyric acid metabolism as well as those encoding ion-transport ATPase are up-regulated in both oxt and oxtr1 mutants only in female medaka, potentially explaining the sex difference of the mutant phenotype. Our findings provide genetic evidence that oxt-oxtr1 signaling plays a role in the mate choice for familiar individuals in a sex-specific manner in medaka fish.

    DOI: 10.1073/pnas.1921446117

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  • Neuropeptide B mediates female sexual receptivity in medaka fish, acting in a female-specific but reversible manner 査読

    Towako Hiraki-Kajiyama, Junpei Yamashita, Keiko Yokoyama, Yukiko Kikuchi, Mikoto Nakajo, Daichi Miyazoe, Yuji Nishiike, Kaito Ishikawa, Kohei Hosono, Yukika Kawabata-Sakata, Satoshi Ansai, Masato Kinoshita, Yoshitaka Nagahama, Kataaki Okubo

    eLife   8   e39495   2019年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.7554/eLife.39495

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  • A collection of transgenic medaka strains for efficient site-directed transgenesis mediated by phiC31 integrase. 査読

    Tokiro Ishikawa, Satoshi Ansai, Masato Kinoshita, Kazutoshi Mori

    G3: Genes, Genomes, Genetics   8 ( 8 )   2585 - 2593   2018年8月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1534/g3.118.200130

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  • Deficiency of Serotonin in Raphe Neurons and Altered Behavioral Responses in Tryptophan Hydroxylase 2-Knockout Medaka (Oryzias latipes) 査読

    Satoshi Ansai, Hiroshi Hosokawa, Shingo Maegawa, Kiyoshi Naruse, Youhei Washio, Kenji Sato, Masato Kinoshita

    Zebrafish   14 ( 6 )   495 - 507   2017年12月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:MARY ANN LIEBERT, INC  

    Serotonin (5-hydroxytryptamine [5-HT]) is a bioactive monoamine that acts as a neurotransmitter in the central and peripheral nervous system of animals. Teleost fish species have serotonergic neurons in the raphe nuclei of the brainstem; however, the role of 5-HT in the raphe neurons in teleost fish remains largely unknown. Here, we established a medaka (Oryzias latipes) strain with targeted disruption of tryptophan hydroxylase 2 (tph2) gene that is involved in the 5-HT synthesis in the raphe nuclei. Immunohistochemistry and mass spectrometry analysis revealed that the homozygous mutants (tph2(13/13)) lacked the ability to synthesize 5-HT in the raphe neurons. To investigate the effects of 5-HT deficiency in adult behaviors, the mutant fish were subjected to five behavioral paradigms (diving, open-field, light-dark transition, mirror-biting, and two-fish social interaction). The homozygous mutation caused a longer duration of freezing response in all examined paradigms and reduced the number of entries to the top area in the diving test. In addition, the mutants exhibited a decreased number of mirror-biting in the males and an increased contact time in direct social interaction between the females. These results indicate that this tph2-knockout medaka serves as a good model to analyze the effects of 5-HT deficiency in the raphe neurons.

    DOI: 10.1089/zeb.2017.1452

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  • Genotyping-free selection of double allelic gene edited medaka using two different fluorescent proteins. 査読

    Yu Murakami, Satoshi Ansai, Akari Yonemura, Masato Kinoshita

    Bio-protocol,   7 ( 24 )   e2665   2017年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.21769/BioProtoc.2665

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  • Loss of zinc finger MYND-type containing 10 (zmynd10) affects cilia integrity and axonemal localization of dynein arms, resulting in ciliary dysmotility, polycystic kidney and scoliosis in medaka (Oryzias latipes) 査読

    Daisuke Kobayashi, Anshin Asano-Hoshino, Takashi Nakakura, Toshiyuki Nishimaki, Satoshi Ansai, Masato Kinoshita, Motoyuki Ogawa, Haruo Hagiwara, Takahiko Yokoyama

    Developmetal Biology   430 ( 1 )   69 - 79   2017年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Cilia and flagella are hair-like organelles that project from the cell surface and play important roles in motility and sensory perception. Motility defects in cilia and flagella lead to primary ciliary dyskinesia (PCD), a rare human disease. Recently zinc finger MYND-type containing 10 (ZMYND10) was identified in humans as a PCD-associated gene. In this study, we use medaka fish as a model to characterize the precise functions of zmynd10. In medaka, zmynd10 is exclusively expressed in cells with motile cilia. Embryos with zmynd10 Morpholino knockdown exhibited a left-right (LR) defect associated with loss of motility in Kupffer's vesicle (KV) cilia. This immotility was caused by loss of the outer dynein arms, which is a characteristic ultrastructural phenotype in PCD. In addition, KV cilia in zmynd10 knockdown embryos had a swollen and wavy morphology. Together, these results suggest that zmynd10 is a multi-functional protein that has independent roles in axonemal localization of dynein arms and in formation and/or maintenance of cilia. The C-terminal region of zmynd10 has a MYND-type zinc finger domain (zf-MYND) that is important for its function. Our rescue experiment showed that the zmynd10-Delta C truncated protein, which lacks zf-MYND, was still partially functional, suggesting that zmynd10 has another functional domain besides zf-MYND. To analyze the later stages of development, we generated a zmynd10 knockout mutant using transcription activator-like effector nuclease (TALEN) technology. Adult mutants exhibited sperm dysmotility, scoliosis and progressive polycystic kidney.

    DOI: 10.1016/j.ydbio.2017.08.016

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  • An efficient system for homology-dependent targeted gene integration in medaka (Oryzias latipes) 査読

    Yu Murakami, Satoshi Ansai, Akari Yonemura, Masato Kinoshita

    Zoological Letters   3 ( 1 )   10   2017年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BioMed Central Ltd.  

    Background The CRISPR/Cas system is a powerful genome editing tool that enables targeted genome modifications in various organisms. In medaka (Oryzias latipes), targeted mutagenesis with small insertions and deletions using this system have become a robust technique and are now widely used. However, to date there have been only a small number of reports on targeted gene integration using this system. We thus sought in the present study to identify factors that enhance the efficiency of targeted gene integration events in medaka. Results We show that longer homology arms (ca. 500 bp) and linearization of circular donor plasmids by cleavage with bait sequences enhances the efficiency of targeted integration of plasmids in embryos. A new bait sequence, BaitD, which we designed and selected by in silico screening, achieved the highest efficiency of the targeted gene integration in vivo. Using this system, donor plasmids integrated precisely at target sites and were efficiently transmitted to progeny. We also report that the genotype of F 2 siblings, obtained by mating of individuals harboring two different colors of fluorescent protein genes (e.g. GFP and RFP) in the same locus, can be easily and rapidly determined non-invasively by visual observations alone. Conclusion We report that the efficiency of targeted gene integration can be enhanced by using donor vectors with longer homologous arms and linearization using a highly active bait system in medaka. These findings may contribute to the establishment of more efficient systems for targeted gene integration in medaka and other fish species.

    DOI: 10.1186/s40851-017-0071-x

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  • Genome editing of medaka 招待 査読

    Satoshi Ansai, Masato Kinoshita

    Methods in Molecular Biology   1630   175 - 188   2017年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:論文集(書籍)内論文   出版者・発行元:Humana Press Inc.  

    Medaka (Oryzias latipes), along with zebrafish (Danio rerio), is a useful experimental model fish. Here, we describe a simple method for generating medaka gene knock-out strains using an automated microchip electrophoresis system. We also describe a method for targeted gene knock-in using a plasmid carrying a sequence that does not cause off-target effects in medaka.

    DOI: 10.1007/978-1-4939-7128-2_15

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  • ADAM12-deficient zebrafish exhibit retardation in body growth at the juvenile stage without developmental defects 査読

    Yudai Tokumasu, Atsuo Iida, Zi Wang, Satoshi Ansai, Masato Kinoshita, Atsuko Sehara-Fujisawa

    Development, Growth & Differentiation   58 ( 4 )   409 - 421   2016年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    ADAM (a disintegrin and metalloprotease) constitutes a family of multi-domain proteins that are involved in development, homeostasis, and disease. ADAM12 plays important roles in myogenesis and adipogenesis in mice; however, the precise physiological mechanisms are not known, and the function of this gene in other vertebrates has not been examined. In this study, we used a simple model vertebrate, the zebrafish, to investigate the functions of ADAM12 during development. Zebrafish adam12 is conserved with those of mammals in the synteny and the amino-acid sequence. We examined adam12 expression in zebrafish embryos by whole mount insitu hybridization and the promoter activity of the adam12 upstream sequence. We found that adam12 is strongly expressed in the cardiovascular system, erythroid progenitors, brain, and jaw cartilage during zebrafish development, and adam12-knockout zebrafish exhibited reduced body size in the juvenile stage without apparent morphological defects. Taken together, these results suggest that adam12 plays a significant role in the regulation of body growth during juvenile stage in zebrafish, although the precise molecular mechanisms await further study.

    DOI: 10.1111/dgd.12286

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  • Chronic fluoxetine treatment induces anxiolytic responses and altered social behaviors in medaka, Oryzias latipes 査読

    Satoshi Ansai, Hiroshi Hosokawa, Shingo Maegawa, Masato Kinoshita

    Behavioural Brain Research   303   126 - 136   2016年4月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Medaka (Oryzias latipes) is a small freshwater teleost that is an emerging model system for neurobehavioral research and toxicological testing. The selective serotonin reuptake inhibitor class of antidepressants such as fluoxetine is one of the widely prescribed drugs, but little is known about the effects of these drugs on medaka behaviors. To assess the behavioral effects of fluoxetine, we chronically administrated fluoxetine to medaka adult fish and analyzed the anxiety-related and social behaviors using five behavioral paradigms (diving, open-field, light-dark transition, mirror-biting, and social interaction) with an automated behavioral testing system. Fish chronically treated with fluoxetine exhibited anxiolytic responses such as an overall increased time spent in the top area in the diving test and an increased time spent in center area in the open-field test. Analysis of socially evoked behavior showed that chronic fluoxetine administration decreased the number of mirror biting times in the mirror-biting test and increased latency to first contact in the social interaction test. Additionally, chronic fluoxetine administration reduced the horizontal locomotor activity in the open-field test but not the vertical activity in the diving test. These investigations are mostly consistent with previous reports in the other teleost species and rodent models. These results indicate that behavioral assessment in medaka adult fish will become useful for screening of effects of pharmaceutical and toxicological compounds in animal behaviors. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.bbr.2016.01.050

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  • Mate-guarding behavior enhances male reproductive success via familiarization with mating partners in medaka fish. 査読 国際誌

    Saori Yokoi, Satoshi Ansai, Masato Kinoshita, Kiyoshi Naruse, Yasuhiro Kamei, Larry J Young, Teruhiro Okuyama, Hideaki Takeuchi

    Frontiers in Zoology   13   21 - 21   2016年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Male-male competition and female mating preference are major mechanisms of sexual selection, which influences individual fitness. How male-male competition affects female preference, however, remains poorly understood. Under laboratory conditions, medaka (Oryzias latipes) males compete to position themselves between a rival male and the female (mate-guarding) in triadic relationships (male, male, and female). In addition, females prefer to mate with visually familiar males. In the present study, to examine whether mate-guarding affects female preference via visual familiarization, we established a novel behavioral test to simultaneously quantify visual familiarization of focal males with females and mate-guarding against rival males. In addition, we investigated the effect of familiarization on male reproductive success in triadic relationships. RESULTS: Three fish (female, male, male) were placed separately in a transparent three-chamber tank, which allowed the male in the center (near male) to maintain closer proximity to the female than the other male (far male). Placement of the wild-type male in the center blocked visual familiarization of the far male by the female via mate-guarding. In contrast, placement of an arginine-vasotocin receptor mutant male, which exhibits mate-guarding deficits, in the center, allowing for maintaining close proximity to the female, did not block familiarization of the far male by the female. We also demonstrated that the reproductive success of males was significantly decreased by depriving females visual familiarization with the males. CONCLUSIONS: Our findings indicated that, at least in triadic relationships, dominance in mate-guarding, not simply close proximity, allows males to gain familiarity with the female over their rivals, which may enhance female preference for the dominant male. These findings focusing on the triadic relationships of medaka may contribute to our understanding of the adaptive significance of persistent mate-guarding, as well as female preference for familiar mates.

    DOI: 10.1186/s12983-016-0152-2

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  • Viable Neuronopathic Gaucher Disease Model in Medaka (Oryzias latipes) Displays Axonal Accumulation of Alpha-Synuclein 査読

    Norihito Uemura, Masato Koike, Satoshi Ansai, Masato Kinoshita, Tomoko Ishikawa-Fujiwara, Hideaki Matsui, Kiyoshi Naruse, Naoaki Sakamoto, Yasuo Uchiyama, Takeshi Todo, Shunichi Takeda, Hodaka Yamakado, Ryosuke Takahashi

    PLOS Genetics   11 ( 4 )   e1005065   2015年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PUBLIC LIBRARY SCIENCE  

    Homozygous mutations in the glucocerebrosidase (GBA) gene result in Gaucher disease (GD), the most common lysosomal storage disease. Recent genetic studies have revealed that GBA mutations confer a strong risk for sporadic Parkinson's disease (PD). To investigate how GBA mutations cause PD, we generated GBA nonsense mutant (GBA-/-) medaka that are completely deficient in glucocerebrosidase (GCase) activity. In contrast to the perinatal death in humans and mice lacking GCase activity, GBA-/- medaka survived for months, enabling analysis of the pathological progression. GBA-/- medaka displayed the pathological phenotypes resembling human neuronopathic GD including infiltration of Gaucher cell-like cells into the brains, progressive neuronal loss, and microgliosis. Detailed pathological findings represented lysosomal abnormalities in neurons and alpha-synuclein (alpha-syn) accumulation in axonal swellings containing autophagosomes. Unexpectedly, disruption of alpha-syn did not improve the life span, formation of axonal swellings, neuronal loss, or neuroinflammation in GBA-/- medaka. Taken together, the present study revealed GBA-/- medaka as a novel neuronopathic GD model, the pahological mechanisms of alpha-syn accumulation caused by GCase deficiency, and the minimal contribution of alpha-syn to the pathogenesis of neuronopathic GD.

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  • An essential role of the arginine vasotocin system in mate-guarding behaviors in triadic relationships of medaka fish (Oryzias latipes). 査読 国際誌

    Saori Yokoi, Teruhiro Okuyama, Yasuhiro Kamei, Kiyoshi Naruse, Yoshihito Taniguchi, Satoshi Ansai, Masato Kinoshita, Larry J Young, Nobuaki Takemori, Takeo Kubo, Hideaki Takeuchi

    PLOS Genetics   11 ( 2 )   e1005009   2015年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Public Library of Science ({PLoS})  

    To increase individual male fitness, males of various species remain near a (potential) mating partner and repel their rivals (mate-guarding). Mate-guarding is assumed to be mediated by two different types of motivation: sexual motivation toward the opposite sex and competitive motivation toward the same sex. The genetic/molecular mechanisms underlying how mate presence affects male competitive motivation in a triadic relationship has remained largely unknown. Here we showed that male medaka fish prominently exhibit mate-guarding behavior. The presence of a female robustly triggers male-male competition for the female in a triadic relationship (2 males and 1 female). The male-male competition resulted in one male occupying a dominant position near the female while interfering with the other male's approach of the female. Paternity testing revealed that the dominant male had a significantly higher mating success rate than the other male in a triadic relationship. We next generated medaka mutants of arginine-vasotocin (avt) and its receptors (V1a1, V1a2) and revealed that two genes, avt and V1a2, are required for normal mate-guarding behavior. In addition, behavioral analysis of courtship behaviors in a dyadic relationship and aggressive behaviors within a male group revealed that avt mutant males displayed decreased sexual motivation but showed normal aggression. In contrast, heterozygote V1a2 mutant males displayed decreased aggression, but normal mate-guarding and courtship behavior. Thus, impaired mate-guarding in avt and V1a2 homozygote mutants may be due to the loss of sexual motivation toward the opposite sex, and not to the loss of competitive motivation toward rival males. The different behavioral phenotypes between avt, V1a2 heterozygote, and V1a2 homozygote mutants suggest that there are redundant systems to activate V1a2 and that endogenous ligands activating the receptor may differ according to the social context.

    DOI: 10.1371/journal.pgen.1005009

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  • Design, evaluation, and screening methods for efficient targeted mutagenesis with transcription activator-like effector nucleases in medaka 招待 査読

    Satoshi Ansai, Keiji Inohaya, Yasutoshi Yoshiura, Manfred Schartl, Norihito Uemura, Ryosuke Takahashi, Masato Kinoshita

    Development, Growth & Differentiation   56 ( 1 )   98 - 107   2014年1月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    Genome editing using engineered nucleases such as transcription activator-like effector nucleases (TALENs) has become a powerful technology for reverse genetics. In this study, we have described efficient detection methods for TALEN-induced mutations at endogenous loci and presented guidelines of TALEN design for efficient targeted mutagenesis in medaka, Oryzias latipes. We performed a heteroduplex mobility assay (HMA) using an automated microchip electrophoresis system, which is a simple and high-throughput method for evaluation of in vivo activity of TALENs and for genotyping mutant fish of F1 or later generations. We found that a specific pattern of mutations is dominant for TALENs harboring several base pairs of homologous sequences in target sequence. Furthermore, we found that a 5 T, upstream of each TALEN-binding sequence, is not essential for genomic DNA cleavage. Our findings provide information that expands the potential of TALENs and other engineered nucleases as tools for targeted genome editing in a wide range of organisms, including medaka.

    DOI: 10.1111/dgd.12104

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  • Targeted disruption of exogenous EGFP gene in medaka using zinc-finger nucleases 査読

    Satoshi Ansai, Hiroshi Ochiai, Yuta Kanie, Yasuhiro Kamei, Yuki Gou, Takeshi Kitano, Takashi Yamamoto, Masato Kinoshita

    Development, Growth & Differentiation   54 ( 5 )   546 - 556   2012年6月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    Zinc-finger nucleases (ZFNs) are artificial enzymes that create site-specific double-strand breaks and thereby induce targeted genome editing. Here, we demonstrated successful gene disruption in somatic and germ cells of medaka (Oryzias latipes) using ZFN to target exogenous EGFP genes. Embryos that were injected with an RNA sequence pair coding for ZFNs showed mosaic loss of green fluorescent protein fluorescence in skeletal muscle. A number of mutations that included both deletions and insertions were identified within the ZFN target site in each embryo, whereas no mutations were found at the non-targeted sites. In addition, ZFN-induced mutations were introduced in germ cells and efficiently transmitted to the next generation. The mutation frequency varied (6100%) in the germ cells from each founder, and a founder carried more than two types of mutation in germ cells. Our results have introduced the possibility of targeted gene disruption and reverse genetics in medaka.

    DOI: 10.1111/j.1440-169X.2012.01357.x

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▼全件表示

書籍等出版物

  • Medaka : Biology, Management, and Experimental Protocols, Volume 2

    Masato Kinoshita, Satoshi Ansai, Yu Murakami( 担当: 分担執筆 ,  範囲: Chapter 7 Genome Editing)

    Wiley-Blackwell  2020年  ( ISBN:9780813808710

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    総ページ数:2 v.   記述言語:英語

    CiNii Books

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  • 遺伝子から解き明かす魚の不思議な世界 : 水面下で起きた4億年の進化物語

    安齋 賢( 担当: 分担執筆 ,  範囲: 第5章 ゲノム編集による魚類研究の新展開)

    一色出版  2019年  ( ISBN:9784909383075

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    総ページ数:iv, 469p   記述言語:日本語

    CiNii Books

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  • Targeted genome editing using site-specific nucleases

    Atsuo Kawahara, Taijiro Yabe, Satoshi Ansai, Shinji Takada, Masato Kinoshita( 担当: 分担執筆 ,  範囲: Genome editing in zebrafish and medaka)

    Springer  2015年 

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  • 実験医学別冊 最強のステップUPシリーズ「今すぐ始めるゲノム編集 - TALEN&CRISPR/Cas9の必須知識と実験プロトコール

    木下 政人, 安齋 賢, 久野 悠, 川原 敦雄( 担当: 分担執筆 ,  範囲: 小型魚類におけるTALENおよびCRISPR/Cas9を用いた遺伝子改変)

    羊土社  2014年 

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MISC

  • インドネシアメダカにおける装飾的な性的二型の多様性とその進化

    安齋 賢

    比較生理生化学   40 ( 2 )   105 - 112   2023年8月

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    記述言語:日本語   出版者・発行元:日本比較生理生化学会  

    性的二型とは,同種の雌雄間で異なる表現型を示す多型現象であリ,様々な分類群で幅広く観察される一方,その表現型自体は多様である。性的二型の進化には,性淘汰と呼ばれる異性をめぐる競争によって生じる淘汰プロセスが重要な役割を果たすことが知られている。しかしながら,性的二型の多様化を担う原因遺伝子の実体が同定された例は少なく,新たな形質の発現に性差が形成される詳細な遺伝機構や新規アリルが集団中に広まるプロセスなど,その詳細な進化遺伝機構には不明な点が多い。我々は,様々な形質で顕著に多様化した性的二型を示し,かつフィールド調査から実験室レベルでの検証までを一貫して行うことが可能なモデルとしてインドネシア・スラウェシのメダカ科魚類固有種群に着目し,その解明に取り組んでいる。本稿では,主に固有種群の1種であるウォウォラエメダカのオス特異的に発現する胸鰭の赤色婚姻色に関する実際の解析例を紹介し,現状明らかになった点と今後の課題について議論する。併せて,幅広い研究分野への活用を期待し,比較生物学モデルとしてのメダカ科魚類の利点も紹介したい。

    DOI: 10.3330/hikakuseiriseika.40.105

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  • ベクターを利用した細菌のメダカへの投与の検討

    郷龍希, 彦坂悠衣, 亀井保博, 坂本丞, 坂本丞, 安齋賢, 神谷重樹

    日本分子生物学会年会プログラム・要旨集(Web)   46th   2023年

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  • メダカのヒレをつくる–ヒレのかたちの雌雄差と遺伝の仕組み–

    安齋 賢

    月刊アクアライフ 11月号   2022年10月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(商業誌、新聞、ウェブメディア)  

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  • 遺伝子から探るウォウォラエメダカにおける赤色ヒレの進化 招待

    安齋 賢

    月刊アクアライフ 5月号   2021年4月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(商業誌、新聞、ウェブメディア)  

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  • 性経験のないオスメダカは初めての性的パートナーに対して配偶者選好性を示す

    大門将寛, 安齋賢, 勝村啓史, 坂本浩隆, 竹内秀明

    日本動物行動学会大会発表要旨集   40th (CD-ROM)   2021年

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  • 配偶者選択におけるオキシトシンの役割の性的二形性

    横井佐織, 成瀬清, 亀井保博, 安齋賢, 木下政人, 水戸麻理, 岩崎信太郎, 井ノ上俊太郎, 奥山輝大, 中川真一, YOUNG Larry J., 竹内秀明

    日本分子生物学会年会プログラム・要旨集(Web)   43rd   2020年

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  • 魚類におけるゲノム編集技術の現状 招待

    安齋 賢

    月刊 海洋   49 ( 4 )   196 - 201   2017年4月

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    担当区分:筆頭著者, 責任著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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講演・口頭発表等

  • セントロメアの再配置よるメダカ属魚類の核型進化

    安齋 賢, 北野 潤

    日本動物学会第94回山形大会  2023年9月8日 

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    開催年月日: 2023年9月7日 - 2023年9月9日

    記述言語:日本語   会議種別:口頭発表(一般)  

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  • メダカ属魚類の核型進化におけるセントロメア再配置

    安齋 賢, 北野 潤

    日本進化学会第25回沖縄大会  2023年9月1日 

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    開催年月日: 2023年8月31日 - 2023年9月3日

    記述言語:日本語   会議種別:口頭発表(一般)  

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  • Toward understanding of the molecular and neuronal basis of diversified sexually selected traits in Sulawesian medaka fishes

    Satoshi Ansai

    EMBO | COB Workshop 'Trans-Scale Biology' using exotic non-model organisms  2023年7月26日 

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    開催年月日: 2023年7月25日 - 2023年7月27日

    記述言語:英語   会議種別:ポスター発表  

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  • 小型魚類モデルにおけるゲノム編集技術の開発状況とその利用 招待

    安齋 賢

    日本ゲノム編集学会 第8回大会  2023年6月6日 

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    開催年月日: 2023年6月6日 - 2023年6月8日

    記述言語:日本語  

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  • ササウシノシタHeteromycteris japonicaの参照ゲノム配列決定

    安齋 賢, 横井 勇人, 鈴木 徹, 宇治 督

    令和5年度日本水産学会春季大会  2023年3月30日 

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    開催年月日: 2023年3月28日 - 2023年3月31日

    記述言語:日本語   会議種別:口頭発表(一般)  

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  • メダカ科魚類の多様性を司るゲノム基盤の解明に向けて 招待

    安齋 賢

    NGS発生生物学現場の会2022  2022年12月6日 

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    開催年月日: 2022年12月6日 - 2022年12月7日

    記述言語:日本語  

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  • Toward understanding the genetic basis of phenotypic diversities of Sulawesian and Japanese medaka fishes 招待

    Satoshi Ansai

    EMBL-EBI Virtual Course: Using fish models to explore the impact of Gene by Environment (GxE) 2022  2022年10月17日 

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    開催年月日: 2022年10月17日 - 2022年10月18日

    記述言語:英語  

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  • ゲノム編集で明らかにするスラウェシ島メダカ固有種群における性的二型多様化の原因遺伝子 招待

    安齋 賢

    第56回魚類学会年会  2022年9月20日 

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    開催年月日: 2022年9月17日 - 2022年9月20日

    記述言語:日本語   会議種別:シンポジウム・ワークショップ パネル(指名)  

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  • メダカにおける遺伝子ノックイン・染色体編集技術の開発とその利用 招待

    安齋 賢

    日本動物学会第93回早稲田大会  2022年9月9日 

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    開催年月日: 2022年9月8日 - 2022年9月10日

    記述言語:日本語   会議種別:シンポジウム・ワークショップ パネル(指名)  

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  • The evolutionary basis of diversified sexually selected traits in Indonesian medaka fishes 招待

    Satoshi Ansai

    日本発生生物学会第55回大会  2022年5月31日 

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    開催年月日: 2022年5月31日 - 2022年6月3日

    記述言語:日本語   会議種別:シンポジウム・ワークショップ パネル(指名)  

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  • インドネシアのメダカ科固有種群における性的二型多様化の分子機構 招待

    安齋 賢, 山平 寿智, 北野 潤

    第44回日本分子生物学会年会  2021年12月3日 

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    開催年月日: 2021年12月1日 - 2021年12月3日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • Sex chromosome turnover in Sulawesian medaka fishes

    Satoshi Ansai, Kawilarang W. A. Masengi, Kazunori Yamahira, Jun Kitano

    ESEB Satellite Symposia 2021 - The remarkable diversity in the rate and mechanisms of sex chromosome evolution  2021年8月31日 

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    開催年月日: 2021年8月30日 - 2021年9月1日

    記述言語:英語   会議種別:口頭発表(一般)  

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  • メダカ科魚類におけるセントロメアの転換と染色体進化 招待

    安齋 賢

    日本進化学会第23回大会  2021年8月18日 

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    開催年月日: 2021年8月18日 - 2021年8月21日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • Genome editing reveals fitness effects of a gene for sexual dichromatism in Sulawesian fish 招待

    Satoshi Ansai

    Japan-Norway Symposium on Fish Endocrinology and Genomics  2021年6月15日 

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    開催年月日: 2021年6月14日 - 2021年6月15日

    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • ゲノム編集から明らかにする性的二型原因遺伝子の適応度への影響

    安齋 賢

    日本生態学会第68回全国大会  2021年3月17日 

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    開催年月日: 2021年3月17日 - 2021年3月21日

    記述言語:日本語   会議種別:口頭発表(一般)  

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  • Fitness effects of a gene underlying sexual dichromatism in a tropical fish revealed by genome editing

    Satoshi Ansai

    EMBO|EMBL Symposium: The Molecular Basis and Evolution of Sexual Dimorphism  2020年9月14日 

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    開催年月日: 2020年9月14日 - 2020年9月16日

    記述言語:英語   会議種別:ポスター発表  

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  • メダカ近縁種における赤色婚姻色の進化機構

    安齋 賢, 山平 寿智, 北野 潤

    第32回日本行動神経内分泌研究会(JSBN2020)  2020年9月1日 

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    開催年月日: 2020年9月1日 - 2020年9月2日

    記述言語:日本語   会議種別:口頭発表(一般)  

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  • スラウェシ島のメダカ科固有種群における性的二型多様化の分子メカニズム

    安齋 賢

    日本動物学会 第90回 大阪大会  2019年9月13日 

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    開催年月日: 2019年9月12日 - 2019年9月14日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • Improved methods for targeted gene knock-in in medaka

    Satoshi Ansai, Kiyoshi Naruse

    The 25th Japanese Medaka and Zebrafish Meeting  2019年9月4日 

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    開催年月日: 2019年9月4日 - 2019年9月5日

    記述言語:日本語   会議種別:ポスター発表  

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  • ゲノム編集技術とその進化生物学研究への展開 招待

    安齋 賢

    日本進化学会第21回大会  2019年8月7日 

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    開催年月日: 2019年8月7日 - 2019年8月10日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • Adrianichthyidae in Sulawesi: as a model system to explore the mechanisms underlying diversification in sexual dimorphism 招待

    Satoshi Ansai

    The 14th International Zebrafish Conference  2019年6月13日 

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    開催年月日: 2019年6月12日 - 2019年6月16日

    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • メダカ属における赤色婚姻色の多様化をもたらす遺伝基盤

    安齋 賢

    平成31年度公益社団法人日本水産学会春季大会  2019年3月28日 

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    開催年月日: 2019年3月26日 - 2019年3月29日

    記述言語:日本語   会議種別:口頭発表(一般)  

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  • スラウェシ島メダカ科固有種群における性的二型の多様化 招待

    安齋 賢

    新学術領域研究「性スペクトラム」第1回若手研究会  2019年3月4日 

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    開催年月日: 2019年3月4日 - 2019年3月5日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • インドネシア・スラウェシ島のメダカ固有種群から探る婚姻色の多様化メカニズム 招待

    安齋 賢

    第13回バイオイメージングフォーラム&重点共同利用研究合同シンポジウム  2019年2月13日 

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    開催年月日: 2019年2月13日 - 2019年2月14日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • メダカから学ぶ性的二型の多様化とその分子基盤 招待

    安齋 賢

    第29回デジタル進化生物セミナー  2023年2月22日 

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    記述言語:日本語  

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  • スラウェシ島のメダカ固有種群における性的二型の多様化メカニズムの解明に向けて

    安齋 賢

    第6回生態進化発生コロキウム  2018年12月28日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • The molecular genetic basis of diversification in sexual dimorphism of medaka species endemic to Sulawesi, Indonesia

    Satoshi Ansai

    THE 46th NAITO CONFERENCE ON Mechanisms of Evolution and Biodiversity  2018年10月3日 

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    記述言語:英語   会議種別:ポスター発表  

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  • Adrianichthyidae species in Sulawesi as a model system to explore the molecular genetic basis of diversification in sexual dimorphism

    Satoshi Ansai

    第24回小型魚類研究会  2018年8月26日 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • メダカ科魚類における性的二型 の多様化をもたらす分子基盤

    安齋賢, 持田浩治, 藤本真悟, Daniel Mokodongan, 永野惇, 豊田敦, 成瀬清, 山平寿智, 北野潤

    日本進化学会第20回大会  2018年8月23日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • The molecular genetic basis of diversification in sexual dimorphism of medaka species endemic to Sulawesi, Indonesia

    Satoshi Ansai

    9th International Conference on Stickleback Behavior and Evolution  2018年7月5日 

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    記述言語:英語   会議種別:ポスター発表  

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  • The molecular genetic basis of diversification in sexual dimorphism of medaka species endemic to Sulawesi, Indonesia

    Satoshi Ansai

    2018 International Zebrafish Conference  2018年6月21日 

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    記述言語:英語   会議種別:ポスター発表  

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  • The molecular genetic basis of diversified sexually dimorphic traits in Oryzias species endemic to Sulawesi, Indonesia

    Satoshi Ansai

    4th Strategic Meeting for Medaka Research  2018年4月17日 

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    記述言語:英語   会議種別:口頭発表(一般)  

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  • ウォウォールメダカにおける体色の性的二型の遺伝基盤

    安齋 賢, 持田浩治, 藤本真悟, Daniel F. Mokodongan, 永野惇, 山平寿智, 北野潤

    第88回日本動物学会大会  2017年9月20日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • メダカ科魚類における性的二型の多様化をもたらす遺伝基盤

    安齋 賢

    第10回Evo-devo青年の会  2017年6月17日 

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    記述言語:日本語   会議種別:ポスター発表  

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  • メダカ科魚類における性的二型の多様化をもたらす遺伝基盤

    安齋 賢, 持田浩治, 藤本真悟, Daniel F. Mokodongan, 永野惇, 山平寿智, 北野潤

    第64回日本生態学会大会  2017年3月15日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • 魚類における遺伝子改変技術の現状 招待

    安齋 賢, 木下 政人

    東京大学大気海洋研究所 共同利用研究集会「海洋生物の適応戦略:新規技術・現象からの新展開」  2016年9月15日 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • The genetic basis of sexually dimorphic traits in Oryzias woworae: Toward the understanding of the genetic basis for phenotypic diversification in Indonesian medakas

    Satoshi Ansai, Koji Mochida, Shingo Fujimoto, Daniel F. Mokodongan, Atsushi J. Nagano, Kazunori Yamahira, Jun Kitano

    22th Japanese Medaka and Zebrafish Meeting  2016年8月21日 

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    記述言語:英語   会議種別:口頭発表(一般)  

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  • スラウェシ島のメダカ科魚類における表現型多様化の遺伝基盤—新たな進化遺伝学モデルとしてのメダカについて考える

    安齋 賢

    第2回ユニークな少数派実験動物を扱う若手が最先端アプローチを勉強する会  2016年8月21日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • Behavioral alterations in medaka caused by serotonin deficiency in the raphe neurons

    Satoshi Ansai, Hiroshi Hosokawa, Shingo Maegawa, Youhei Washio, Kenji Sato, Masato Kinoshita

    17th Australia and New Zealand Zebrafish Meeting  2016年2月5日 

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    記述言語:英語   会議種別:ポスター発表  

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  • Behavioral alterations in medaka caused by serotonin deficiency in the raphe neurons

    Satoshi Ansai, Hiroshi Hosokawa, Shingo Maegawa, Youhei Washio, Kenji Sato, Masato Kinoshita

    3rd Medaka Strategic Meeting  2016年2月1日 

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    記述言語:英語   会議種別:ポスター発表  

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  • 小型魚類におけるゲノム編集技術の現状 招待

    川原 敦雄, 安齋 賢, 大道 裕

    21th Japanese Medaka and Zebrafish Meeting  2015年9月20日 

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    記述言語:日本語   会議種別:シンポジウム・ワークショップ パネル(指名)  

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  • PhiC31インテグレースによる高効率遺伝子導入に用いるLanding site (attP) 導入メダカ系統の樹立

    石川 時郎, 安齋 賢°, 岡田 徹也, 木下 政人, 森 和俊

    21th Japanese Medaka and Zebrafish Meeting  2015年9月19日 

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    記述言語:日本語   会議種別:ポスター発表  

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  • Behavioral phenotyping test battery for genetically modified fish

    Satoshi Ansai, Shingo Maegawa, Masato Kinoshita, Hiroshi Hosokawa

    20th Japanese Medaka and Zebrafish Meeting  2014年9月22日 

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    記述言語:英語   会議種別:口頭発表(一般)  

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  • 遺伝子改変メダカの行動特性解析のための行動テストバッテリーの開発

    安齋 賢, 前川 真吾, 木下 政人, 細川 浩

    日本動物学会第85回仙台大会  2014年9月11日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • Efficient method for targeted mutagenesis in medaka using TALENs and CRISPR/Cas system

    Satoshi Ansai, Masato Kinoshita

    11th International Conference on Zebrafish Development and Genetics  2014年6月24日 

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    記述言語:英語   会議種別:ポスター発表  

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  • Efficient and simple method for targeted mutagenesis in medaka using TALENs and CRISPR/Cas system

    Satoshi Ansai, Masato Kinoshita

    2nd Strategical Meeting for Medaka Research  2014年4月10日 

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    記述言語:英語   会議種別:ポスター発表  

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  • CRISPR/Casシステムを利用したメダカにおける簡便・高効率な標的遺伝子破壊

    安齋 賢, 木下 政人

    第36回日本分子生物学会年会  2013年12月5日 

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    記述言語:日本語   会議種別:ポスター発表  

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  • TALEN及びCRISPR/Casを用いた標的遺伝子破壊メダカ作出技術の確立

    安齋 賢, 木下 政人

    第10回水生動物の行動と神経系シンポジウム  2013年11月30日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • CRISPR/Casシステムによる遺伝子破壊メダカの作出

    安齋 賢, 木下 政人

    日本動物学会第84回岡山大会  2013年9月27日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • CRISPR/Cas system - an efficient and simple tool for targeted genome editing in medaka

    Satoshi Ansai, Masato Kinoshita

    19th Japanese Medaka and Zebrafish Meeting  2013年9月20日 

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    記述言語:英語   会議種別:ポスター発表  

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  • Targeted disruption endogenous genes in medaka using TALENs

    Satoshi Ansai, Tetsushi Sakuma, Takashi Yamamoto, Norihito Uemura, Ryosuke Takahashi, Masato Kinoshita

    第35回日本分子生物学会年会  2012年12月12日 

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    記述言語:英語   会議種別:ポスター発表  

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  • Targeted mutagenesis in medaka using custom-designed TALENs

    Satoshi Ansai, Tetsushi Sakuma, Takashi Yamamoto, Norihito Uemura, Ryosuke Takahashi, Masato Kinoshita

    18th Japanese Medaka and Zebrafish Meeting  2012年9月22日 

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    記述言語:英語   会議種別:ポスター発表  

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  • Current status of gene knockout in medaka

    Satoshi Ansai, Hiroshi Ochiai, Tetsushi Sakuma, Takashi Yamamoto, Masato Kinoshita

    18th Japanese Medaka and Zebrafish Meeting  2012年9月22日 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • TALENを用いたメダカ内在性遺伝子の破壊

    安齋 賢, 上村 紀仁, 高橋 良輔, 木下 政人

    第2回ゲノム編集研究会  2012年9月20日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • メダカでのZFN, TALENの最適化を目指して

    安齋 賢, 谷口 善仁, 北野 健, 木下 政人

    第1回ゲノム編集研究会  2012年2月28日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

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  • Targeted gene disruption in medaka using zinc-finger nucleases

    Satoshi Ansai, Yuki Gou, Takeshi Kitano, Hiroshi Ochiai, Yasuhiro Kamei, Takashi Yamamoto, Masato Kinoshita

    第34回日本分子生物学会年会  2011年12月13日 

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    記述言語:英語   会議種別:ポスター発表  

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▼全件表示

受賞

  • Best Poster Award

    2016年2月   17th Australia and New Zealand Zebrafish Meeting  

    安齋 賢

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  • Best Poster Award

    2013年9月   19th Japanese Medaka and Zebrafish Meeting  

    安齋 賢

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  • Best Poster Award

    2012年9月   18th Japanese Medaka and Zebrafish Meeting  

    安齋 賢

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共同研究・競争的資金等の研究

  • 性決定システムの転換をもたらした進化メカニズムの解明

    研究課題/領域番号:23H02524  2023年04月 - 2027年03月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    竹花 佑介, 安齋 賢

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    配分額:18720000円 ( 直接経費:14400000円 、 間接経費:4320000円 )

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  • 装飾形質をシグナルとした配偶者選好性を司る神経基盤の解明

    研究課題/領域番号:23H02513  2023年04月 - 2026年03月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    安齋 賢, 竹内 秀明

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    配分額:18850000円 ( 直接経費:14500000円 、 間接経費:4350000円 )

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  • 魚類ソーシャルビジョンの分子・遺伝基盤の解明

    研究課題/領域番号:21H04773  2021年04月 - 2025年03月

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    竹内 秀明, 安齋 賢

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    配分額:42900000円 ( 直接経費:33000000円 、 間接経費:9900000円 )

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  • 熱帯の多様性創出における急速な性染色体置換の役割

    研究課題/領域番号:21H04782  2021年04月 - 2024年03月

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    山平 寿智, 北野 潤, 安齋 賢

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    配分額:42120000円 ( 直接経費:32400000円 、 間接経費:9720000円 )

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  • メダカ黒色婚姻色の多様化をもたらす性的葛藤遺伝子の同定

    研究課題/領域番号:21K15143  2021年04月 - 2023年03月

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    安齋 賢

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    配分額:4550000円 ( 直接経費:3500000円 、 間接経費:1050000円 )

    雌雄間で有利な表現型が異なる状態、すなわち性的葛藤状態は、性的二型を進化させる主要な原動力であると考えられている。しかし、性的葛藤形質の原因遺伝子を同定し、その機能解析からそれらの遺伝子が性的葛藤状態にあることを実証し、さらにその解消に関わる詳細な遺伝機構を明らかにした例はない。本研究では、黒色婚姻色パターンと性染色体の急速な種間変異を有するインドネシア・スラウェシのポソ湖メダカ科固有種群をモデルとして、特に黒色婚姻色の原因遺伝子同定から性的葛藤遺伝子の同定を目指す。更に、同定した原因遺伝子についてゲノム編集による機能解析を行うことで、同定した遺伝子が性的葛藤状態にあることを実証することを目的とする。
    本年度は、遺伝学的解析による黒色婚姻色パターンの変異に関わる遺伝子座の同定と、各固有種群における性決定遺伝子の絞り込みを中心に行った。遺伝学的解析では、解析に必要な種間雑種(F2またはBC1)家系の作出およびサンプリングが完了した。現在、各家系についてSNPタイピングを進行中であり、その後のQTL解析についても表現型解析を準備中である。性決定遺伝子座の同定に向けては、ddRAD-seqにより取得したゲノムワイドSNPを用いた解析や、Pool-seqによる雌雄間の全ゲノム比較解析を行ったものの、いずれの解析でも性染色体のシグナルが弱く、性決定遺伝子座の絞り込みにつながるような再現性のある結果が得られていない。現在、より精度の高い手法として、野外採集個体の全ゲノムシーケンスデータを使用したゲノムワイド関連解析により、性決定遺伝子座の解析を行うことを計画中である。

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  • 種分化を規定するゲノム構造

    2020年11月 - 2026年03月

    科学技術振興機構  戦略的創造研究推進事業 CREST  ゲノムスケールのDNA設計・合成による細胞制御技術の創出

    北野 潤, 山平 寿智, 安齋 賢

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    担当区分:研究分担者 

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  • XY型からZW型への性決定システムの進化

    研究課題/領域番号:19H03269  2019年04月 - 2023年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    竹花 佑介, 安齋 賢

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    配分額:17160000円 ( 直接経費:13200000円 、 間接経費:3960000円 )

    本研究では、互いに近縁でありながら異なる性決定システム(XY型およびZW型)を示すメダカ属javanicusグループの4種について、全種から性決定遺伝子を同定することで、XY型からZW型が生じた進化メカニズムを解明することを目的としている。本年度は、ゲノムシークエンスを用いた性決定遺伝子候補の探索を中心に、以下の実験を行った。
    ZW型のジャワメダカとハブスメダカについては、Z染色体あるいはW染色体のみをもつ半数体胚を作出し、それぞれからIlluminaデータを取得した。これをすでに構築したジャワメダカの参照配列にマッピングすることで、Z染色体とW性染色体の間でカバレージが異なる領域や遺伝的分化が認められる領域を特定した。ジャワメダカについては、W染色体特異的なPacBioコンティグが見出され、この中に性決定遺伝子が含まれている可能性が考えられる。また、ジャワメダカの実験系統の原産地にあたるペナン(マレーシア)にて野生集団を採集し、実験系統で確立した性連鎖マーカーを用いて遺伝的性(ZZあるいはZW)を確認した。ZZはすべてオス、ZWはすべてメスであったことから、野生集団が実験系統と同一の性決定機構をもつことが確認できた。一方、XY型のタイメダカについては、集団ゲノミクス解析によって、その性染色体と性決定遺伝子座を特定した。XY型のハウザンメダカについては、Y染色体特異的にDmrt1が10コピー以上遺伝子重複していることを見出した。これらY染色体のDmrt1をノックアウトするとXY個体がメスに性転換したことから、本遺伝子が性決定遺伝子であるこが強く示唆された。

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  • 失われた野性味から明らかにする自然環境特異的な生体調節のメカニズム

    研究課題/領域番号:18K19323  2018年06月 - 2021年03月

    日本学術振興会  科学研究費助成事業 挑戦的研究(萌芽)  挑戦的研究(萌芽)

    神田 真司, 安齋 賢, 馬谷 千恵, 兵藤 晋

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    配分額:6370000円 ( 直接経費:4900000円 、 間接経費:1470000円 )

    本年度はd-rR メダカと野生メダカのF1ハイブリッドそして F2ハイブリッドを作成した。 まず、F0個体の各種表現型を解析したところ、当初の期待通り、d-rR メダカと野生メダカは様々な表現型の違いを表していた。これらの見た目で観察された表現型を、それぞれ定量し、解析したところ、成長や繁殖・ストレスなど、様々な表現型において有意に差があることが分かった。そこでF2ハイブリッドを用いて同様の表現型解析を行ったところ、ちょうどd-rR メダカと野生メダカの間を取るような表現型の分布を示したため、本研究で期待しているような遺伝子による表現型の差が出ているという事が強く示唆された。本年度は、この表現型をさらに遺伝子型の解析として行うために、各種実験系の整備及びゲノム解析に向けたゲノム抽出の条件検討、最適なシーケンス法の検討を行った。現在、両系統のF0世代および200匹以上のF2ハイブリッドの表現型解析を終えており、これから最適な条件でのゲノム抽出・サンプル調製を行い、次世代シーケンサーによるすべての個体のゲノム解析を行う段階にさしかかっている。また、F2個体をさらに増やし、表現型解析も続けている。これらの解析および次世代シーケンサーによるシーケンスの後には、今回明らかにした表現型に関与する遺伝子座の決定がなされると期待される。これまでに研究分担者のそれぞれの技術をいかし、密に連携した研究ができ、概ね順調に進展していると考えている。

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  • メダカ科魚類における性的二型多様化の進化遺伝機構

    研究課題/領域番号:18K14769  2018年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    安齋 賢

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    配分額:4160000円 ( 直接経費:3200000円 、 間接経費:960000円 )

    性的二型の多様化に関わる進化・遺伝メカニズムを解明するため、インドネシア・スラウェシ島のメダカ科固有種のウォウォールメダカが示す雄の婚姻色(胸鰭の赤色)をモデルに研究を行った。QTL解析とRNA-seq解析から同定した常染色体上の候補遺伝子について、CRISPR/Casシステムを用いて変異体を作出し、赤色の発現に必須であることを示した。またアンドロゲン投与実験から、アンドロゲンシグナルが発現の性差の形成に重要であることを示した。さらに、変異体を用いた配偶行動実験と捕食実験から、赤色の欠失が配偶者選好性を低下させ、捕食者を誘引することが明らかとなった。

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  • メダカ科魚類における性的葛藤遺伝子の同定と機能解析

    研究課題/領域番号:16J05534  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    安齋 賢

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    配分額:4420000円 ( 直接経費:3400000円 、 間接経費:1020000円 )

    本研究は、性的二型の多様化に関わる分子機構を解明し、雌雄の適応度に与える影響を含めて実験的に証明することを目的として、インドネシア・スラウェシ島のメダカ科魚類固有種における体色の性的二型をモデルとした研究を進めている。前年度までに、ウォウォールメダカ (Oryzias woworae) の雄が発現する鮮やかな体色(赤い胸鰭と青い体側)について、種間交雑家系を用いたQTL解析を行い、原因遺伝子座の同定を試みた。その結果、赤い胸鰭の有無が常染色体上の1遺伝子座によって制御されている可能性を見出した。本年度はまず、(1)胸鰭におけるRNA-seqによる網羅的遺伝子発現解析により、胸鰭で発現に雌雄差のある遺伝子を計735個同定した。この内、18個がQTL解析により同定した原因遺伝子座内に含まれており、その中から有力な候補遺伝子を同定した。続いて同定した候補遺伝子について、(2)F2雑種個体を用いたアリル特異的発現解析を行った所、雌雄どちらにおいてもウォウォールメダカ由来アリルの発現量が有意に高い事が明らかとなった。このことは、原因遺伝子のシス調節領域の変異が胸鰭の高発現に重要であることを示唆している。さらに(3)雌の配偶者選択行動に対する胸鰭色彩の影響を解析するため、予備的な行動実験を行った。赤色フィルター下の行動実験で、赤い胸鰭を持つ種への選好性が低下する傾向が見られたことから、胸鰭の色彩が配偶者選好に重要である可能性が示された。

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  • 脊椎動物の社会性行動の遺伝・神経基盤の解明

    研究課題/領域番号:16H04819  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    成瀬 清, 安齋 賢, 竹内 秀明, 横井 佐織, 深町 昌司

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    配分額:16770000円 ( 直接経費:12900000円 、 間接経費:3870000円 )

    c-fos/egr1のプロモーターの下流にDD_mClover3をノックインした系統を樹立し、てんかん誘導剤であるPTZを用いて、神経興奮依存にDD_mClover3の発現量が上昇するかを確認した。その結果Tg(c-fos:DD_mClover3)ではDD_mClover3の発現量が約1.5-6倍に上昇した。またTg(egr1:DD_mClover3)系統では同じ処理により発現量が1.9倍に上昇した。
    CRISPR-Cas9を用いたゲノム編集によってSWS1、SWS2、 LWSの各遺伝子に関するKO個体を樹立することができた。またSWS1特異的モノクローナル抗体を得ることができた。

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  • 人工ヌクレアーゼを用いた標的遺伝子組換えメダカ作出技術の確立

    研究課題/領域番号:13J01682  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    安齋 賢

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    配分額:3000000円 ( 直接経費:3000000円 )

    DNAシークエンス技術の発達に伴い、ゲノム情報の整備が急速に進む中、個々の遺伝子の機能を個体レベルで詳細に解析するための逆遺伝学的手法の重要性は増大しつつある。本研究では、任意のゲノムDNAを切断可能な人工ヌクレアーゼを用いて、メダカでの胚における標的遺伝子組換え技術を確立することを目的とした。本年度は前年度に引き続き、CRISPR/Casシステムによる標的遺伝子組み換えの高効率化のための条件検討を行った。
    本研究では、骨格筋特異的に強く発現するOlMA1遺伝子への標的遺伝子組換えによるGFP遺伝子の導入をモデル実験として、導入効率の比較検討を進めた。始めに、特に再現性において問題となった部分として、ドナーDNAへのRNaseの混入、及び転写RNAへのDNaseの混入の2点について、それぞれProteinase処理の追加や精製キットの変更を行った。続いて、必要な各核酸の導入量や導入に用いるドナーベクター中の相同配列の長さ、相同配列を露出させるためのBait配列について、導入効率に及ぼす影響を比較検討し、ある程度効率的に標的遺伝子組換えを行うためのプロトコルを確立しつつある。現在、当初計画の通り、更なる相同組換え効率の上昇を期待して、DNA二重鎖切断修復に関わる分子の操作についても検討を進めている。

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社会貢献活動

  • The 9th NIBB International Practical Course and The 4rd NIBB-TLL Joint International Practical Course, Genetics and Imaging of Medaka and Zebrafish

    役割:講師

    2016年8月18日 - 2016年8月30日

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    種別:研究指導

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  • 2015 メダカベーシックトレーニングコース

    役割:講師

    基礎生物学研究所  2015年8月6日 - 2015年8月7日

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    種別:研究指導

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  • The 8th NIBB International Practical Course and The 3rd NIBB-TLL-DBS/NUS Joint International Practical Course, Experimental Techniques using Medaka and Xenopus – The Merits of using both –

    役割:講師

    基礎生物学研究所  2014年9月22日 - 2014年10月1日

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    種別:研究指導

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  • 人工ヌクレアーゼによる小型魚類の遺伝子破壊法 (TALEN講習会)

    役割:講師

    基礎生物学研究所  2013年2月25日 - 2013年3月1日

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    種別:研究指導

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学術貢献活動

  • 第26回小型魚類研究会

    役割:企画立案・運営等

    2020年11月20日 - 2020年11月21日

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    種別:学会・研究会等 

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