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  

In insect species that undergo long germ segmentation, such as Drosophila, all segments are specified simultaneously at the early blastoderm stage. As embryogenesis progresses, the expression boundaries of Hox genes are established by repression of gap genes, which is subsequently replaced by Polycomb group (PcG) silencing. At present, however, it is not known whether patterning occurs this way in a more ancestral (short germ) mode of embryogenesis, where segments are added gradually during posterior elongation. In this study, two members of the PcG family, Enhancer of zeste (E(z)) and Suppressor of zeste 12 (Su(z) 12), were analyzed in the short germ cricket, Gryllus bimaculatus. Results suggest that although stepwise negative regulation by gap and PcG genes is present in anterior members of the Hox cluster, it does not account for regulation of two posterior Hox genes, abdominal-A (abd-A) and Abdominal-B (Abd-B). Instead, abd-A and Abd-B are predominantly regulated by PcG genes, which is the mode present in vertebrates. These findings suggest that an intriguing transition of the PcG-mediated silencing of Hox genes may have occurred during animal evolution. The ancestral bilaterian state may have resembled the current vertebrate mode of regulation, where PcG-mediated silencing of Hox genes occurs before their expression is initiated and is responsible for the establishment of individual expression domains. Then, during insect evolution, the repression by transcription factors may have been acquired in anterior Hox genes of short germ insects, while PcG silencing was maintained in posterior Hox genes.

DOI： 10.1242/bio.201411064

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記述言語：英語   出版者・発行元：Company of Biologists  

Hemimetabolous insects such as the cricket Gryllus bimaculatus regenerate lost tissue parts using blastemal cells, a population of dedifferentiated proliferating cells. The expression of several factors that control epigenetic modification is upregulated in the blastema compared with differentiated tissue, suggesting that epigenetic changes in gene expression might control the differentiation status of blastema cells during regeneration. To clarify the molecular basis of epigenetic regulation during regeneration, we focused on the function of the Gryllus Enhancer of zeste [Gb'E(z)] and Ubiquitously transcribed tetratricopeptide repeat gene on the X chromosome (Gb'Utx) homologues, which regulate methylation and demethylation of histone H3 lysine 27 (H3K27), respectively. Methylated histone H3K27 in the regenerating leg was diminished by Gb'E(z)RNAi and was increased by Gb'UtxRNAi. Regenerated Gb'E(z)RNAi cricket legs exhibited extra leg segment formation between the tibia and tarsus, and regenerated Gb'UtxRNAi cricket legs showed leg joint formation defects in the tarsus. In the Gb'E(z)RNAi regenerating leg, the Gb'dac expression domain expanded in the tarsus. By contrast, in the Gb'UtxRNAi regenerating leg, Gb'Egfr expression in the middle of the tarsus was diminished. These results suggest that regulation of the histone H3K27 methylation state is involved in the repatterning process during leg regeneration among cricket species via the epigenetic regulation of leg patterning gene expression.

DOI： 10.1242/dev

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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：COMPANY OF BIOLOGISTS LTD  

In the cricket Gryllus bimaculatus, missing distal parts of the amputated leg are regenerated from the blastema, a population of dedifferentiated proliferating cells that forms at the distal tip of the leg stump. To identify molecules involved in blastema formation, comparative transcriptome analysis was performed between regenerating and normal unamputated legs. Components of JAK/STAT signalling were upregulated more than twofold in regenerating legs. To verify their involvement, Gryllus homologues of the interleukin receptor Domeless (Gb'dome), the Janus kinase Hopscotch (Gb'hop) and the transcription factor STAT (Gb'Stat) were cloned, and RNAi was performed against these genes. Gb'dome(RNAi), Gb'hop(RNAi) and Gb'Stat(RNAi) crickets showed defects in leg regeneration. Blastema expression of Gb'cyclinE was decreased in the Gb'Stat(RNAi) cricket compared with that in the control. Hyperproliferation of blastema cells caused by Gb'fat(RNAi) or Gb'warts(RNAi) was suppressed by RNAi against Gb'Stat. The results suggest that JAK/STAT signalling regulates blastema cell proliferation during leg regeneration.

DOI： 10.1242/dev.084590

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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  

In the cricket Gryllus bimaculatus, missing distal parts of amputated legs are regenerated from blastemas based on positional information. The Dachsous/Fat (Ds/Ft) signaling pathway regulates blastema cell proliferation and positional information along the longitudinal axis during leg regeneration. Herein, we show that the Gryllus homologue of Lowfat (Gb'Lft), which modulates Ds/Ft signaling in Drosophila, is involved in leg regeneration. Gb'lft is expressed in regenerating legs, and RNAi against Gb'lft (Gb'lft RNAi) suppressed blastema cell hyperproliferation caused by Gb'ft(RNAi) or Gb'ds(RNAi) but enhanced that caused by Gb'kibra(RNAi) or Gb'warts(RNAi). In Gb'lft RNAi nymphs, missing parts of amputated legs were regenerated, but the length of the regenerated legs was shortened depending on the position of the amputation. Both normal and reversed intercalary regeneration occurred in Gb'lft(RNAi) nymphs, suggesting that Gb'Lft is involved in blastema cell proliferation and longitudinal leg regeneration under the Ds/Ft signaling pathway, but it is not required for intercalary regeneration. Developmental Dynamics 240:1440-1453, 2011. (C) 2011 Wiley-Liss, Inc.

DOI： 10.1002/dvdy.22647

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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：COMPANY OF BIOLOGISTS LTD  

An amputated cricket leg regenerates all missing parts with normal size and shape, indicating that regenerating blastemal cells are aware of both their position and the normal size of the leg. However, the molecular mechanisms regulating this process remain elusive. Here, we use a cricket model to show that the Dachsous/Fat (Ds/Ft) signalling pathway is essential for leg regeneration. We found that knockdown of ft or ds transcripts by regeneration-dependent RNA interference (rdRNAi) suppressed proliferation of the regenerating cells along the proximodistal (PD) axis concomitantly with remodelling of the pre-existing stump, making the regenerated legs shorter than normal. By contrast, knockdown of the expanded (ex) or Merlin (Mer) transcripts induced over-proliferation of the regenerating cells, making the regenerated legs longer. These results are consistent with those obtained using rdRNAi during intercalary regeneration induced by leg transplantation. We present a model to explain our results in which the steepness of the Ds/Ft gradient controls growth along the PD axis of the regenerating leg.

DOI： 10.1242/dev.035204

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Genome searches in this study indicate that the nematode Caenorhabditis elegans genome has 2582 bidirectionally oriented genes that account for more than 25% of the total genes. We analyze the transcriptional repression system for one of these predicted bidirectional promoters, which controls the expression of the spermathecal gene sth-1 and collagen gene col-43. These two genes are separated by 1.3 kb and are transcribed bidirectionally. sth-1 is expressed in spermatheca after the L4 stage and col-43 is expressed in the hypodermal cells of the L2d dauer stage. The upstream regions required for the expression of sth-1 and col-43 shared an overlapped control sequence. Two homeoproteins, MAB-18 and CEH-14, were isolated by yeast one-hybrid screening as binding proteins of the overlapped region. MAB-18 bound to two homeodomain-binding sites and interacted with CEH-14 to repress col-43 expression in spermatheca. These results indicate that the two homeoproteins interact with each other to repress col-43 expression in sth-1-expressing tissues. This is the first report of bidirectional gene regulation analysis in the C.elegans genome.

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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：MDPI AG  

The first event of differentiation and morphogenesis in the optic vesicle (OV) is specification of the neural retina (NR) and retinal pigment epithelium (RPE), separating the inner and outer layers of the optic cup, respectively. Here, we focus on a basic helix-loop-helix gene, BHLHE40, which has been shown to be expressed by the developing RPE in mice and zebrafish. Firstly, we examined the expression pattern of BHLHE40 in the developing chicken eye primordia by in situ hybridization. Secondly, BHLHE40 overexpression was performed with in ovo electroporation and its effects on optic cup morphology and expression of NR and RPE marker genes were examined. Thirdly, we examined the expression pattern of BHLHE40 in LHX1-overexpressed optic cup. BHLHE40 expression emerged in a subset of cells of the OV at Hamburger and Hamilton stage 14 and became confined to the outer layer of the OV and the ciliary marginal zone of the retina by stage 17. BHLHE40 overexpression in the prospective NR resulted in ectopic induction of OTX2 and repression of VSX2. Conversely, BHLHE40 was repressed in the second NR after LHX1 overexpression. These results suggest that emergence of BHLHE40 expression in the OV is involved in initial RPE specification and that BHLHE40 plays a role in separation of the early OV domains by maintaining OTX2 expression and antagonizing an NR developmental program.

DOI： 10.3390/jdb10040045

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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  

<title>Abstract</title>
The circadian clock generates rhythms of approximately 24 h through periodic expression of the clock genes. In insects, the major clock genes <italic>period</italic> (<italic>per</italic>) and <italic>timeless</italic> (<italic>tim</italic>) are rhythmically expressed upon their transactivation by CLOCK/CYCLE, with peak levels in the early night. In <italic>Drosophila</italic>, <italic>clockwork orange</italic> (<italic>cwo</italic>) is known to inhibit the transcription of <italic>per</italic> and <italic>tim</italic> during the daytime to enhance the amplitude of the rhythm, but its function in other insects is largely unknown. In this study, we investigated the role of <italic>cwo</italic> in the clock mechanism of the cricket <italic>Gryllus bimaculatus</italic>. The results of quantitative RT-PCR showed that under a light/dark (LD) cycle, <italic>cwo</italic> is rhythmically expressed in the optic lobe (lamina-medulla complex) and peaks during the night. When <italic>cwo</italic> was knocked down via RNA interference (RNAi), some crickets lost their locomotor rhythm, while others maintained a rhythm but exhibited a longer free-running period under constant darkness (DD). In <italic>cwo</italic>^RNAi crickets, all clock genes except for <italic>cryptochrome 2</italic> (<italic>cry2</italic>) showed arrhythmic expression under DD; under LD, some of the clock genes showed higher mRNA levels, and <italic>tim</italic> showed rhythmic expression with a delayed phase. Based on these results, we propose that <italic>cwo</italic> plays an important role in the cricket circadian clock.

DOI： 10.1186/s40851-020-00166-4

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その他リンク： http://link.springer.com/article/10.1186/s40851-020-00166-4/fulltext.html

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)  

DOI： 10.1371/journal.pone.0240333

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Dickkopf 3 (Dkk3) is a secreted protein belonging to the Dkk family and encoded by the orthologous gene of REIC. Dkk3/REIC is expressed by mouse and human adrenal glands, but the understanding of its roles in this organ is still limited. To determine the functions of Dkk3 in the mouse adrenal gland, we first identified that the mouse Dkk3 protein is N-glycosylated in the adrenal gland as well as in the brain. We performed proteome analysis on adrenal glands from Dkk3-null mice, in which exons 5 and 6 of the Dkk3 gene are deleted. Twodimensional polyacrylamide gel electrophoresis of adrenal proteins from wild-type and Dkk3-null mice revealed 5 protein spots whose intensities were altered between the 2 genotypes. Mass spectrometry analysis of these spots identified binding immunoglobulin protein (BiP), an endoplasmic reticulum (ER) chaperone. To determine whether mouse Dkk3 is involved in the unfolded protein response (UPR), we carried out a reporter assay using ER-stress responsive elements. Forced expression of Dkk3 resulted in the induction of distinct levels of reporter expression, showing the UPR initiated by the ER membrane proteins of activating transcription factor 6 (ATF6) and inositol-requring enzyme 1 (IRE1). Thus, it is possible that Dkk3 is a physiological ER stressor in the mouse adrenal gland.

DOI： 10.18926/AMO/59950

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00441-019-03113-8

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.bbrep.2019.100665

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background | Entrainment to the environmental light cycle is an essential property of the circadian clock. Although the compound eye is known to be the major photoreceptor necessary for entrainment in many insects, the molecular mechanisms of photic entrainment remain to be explored.<br />
Results | We found that cryptochromes (crys) and c-fos mediate photic entrainment of the circadian clock in a hemimetabolous insect, the cricket Gryllus bimaculatus. We examined the effects of RNA interference (RNAi)-mediated knockdown of the cry genes, Gb’cry1 and Gb’cry2, on photic entrainment, and light-induced resetting of the circadian locomotor rhythm. Gb’cry2 RNAi accelerated entrainment for delay shifts, while Gb’cry1/ Gb’cry2 double RNAi resulted in significant lengthening of transient cycles in both advance and delay shifts, and even in entrainment failure in some crickets. Double RNAi also strongly suppressed light induced resetting. The Gb’cry-mediated phase shift or resetting of the rhythm was preceded by light-induced Gb’c-fosB expression. We also found that Gb’c-fosB, Gb’cry2 and Gb’period (Gb’per) were likely co-expressed in some optic lobe neurons.<br />
Conclusion | Based on these results, we propose a novel model for photic entrainment of the insect circadian clock, which relies on the light information perceived by the compound eye.

DOI： 10.1186/s40851-018-0109-8.

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DOI： 10.1111/dgd.12560

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/cga.12304

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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：Elsevier Ltd  

The timeless2 (tim2) gene is an insect orthologue of the mammalian clock gene Timeless (mTim). Although its functional role has been extensively studied in mammals, little is known regarding its role in insects. In the present study, we obtained tim2 cDNA (Gb'tim2) from the cricket Gryllus bimaculatus and characterized its functional role in embryonic development, egg production, and circadian rhythms. Gb'tim2 gave rise to a 1432 amino acid protein, and showed approximately 65% homology to that of Drosophila melanogaster. When treated with parental Gb'tim2RNAi, less than 2% of the treated eggs hatched. On the other hand, control eggs treated with DsRed2RNAi demonstrated a hatching rate of 70%. In most of the Gb'tim2RNAi treated embryos, development was arrested in early stages. Egg production in ovaries of adult virgin females treated with Gb'tim2RNAi was significantly reduced. In addition, while Gb'tim2RNAi crickets exhibited clear locomotor rhythm synchronized with light cycles, their light-on peak was weaker than that of control crickets. Under constant darkness, the activity rhythm of Gb'tim2RNAi crickets was often split into two components running with different periods. Molecular analysis revealed that Gb'tim2RNAi treatment downregulated mRNA levels of Gb'per and Gb'Clk, and enhanced Gb'cyc expression rhythm
no distinct effect was found on Gb'tim expression levels. The change in Gb'per, Gb'Clk and Gb'cyc levels may underlie the altered behavioral rhythms in Gb'tim2RNAi crickets. Both Gb'ClkRNAi and Gb'cycRNAi downregulated Gb'tim2 expression, which suggested that transcription of Gb'tim2 is mediated by Gb'CLK and Gb'CYC through E-box. These results suggested that Gb'tim2 may be involved in both reproduction and circadian rhythm regulation in crickets.

DOI： 10.1016/j.jinsphys.2017.12.007

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

DOI： 10.1016/j.mod.2017.04.427

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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: Animals exhibit circadian rhythms with a period of approximately 24 h in various physiological functions, including locomotor activity. This rhythm is controlled by an endogenous oscillatory mechanism, or circadian clock, which consists of cyclically expressed clock genes and their product proteins. cryptochrome (cry) genes are thought to be involved in the clock mechanism, and their functions have been examined extensively in holometabolous insects, but in hemimetabolous insects their role is less well understood.Results: In the present study, the role of cry genes was investigated using RNAi technology in a hemimetabolous insect, the cricket Gryllus bimaculatus. Using a molecular cloning approach, we obtained cDNAs for two cry genes: Drosophila-type cry1 (Gb ' cry1) and mammalian-type cry2 (Gb'cry2). Gb ' cry2 has six splicing variants, most of which showed rhythmic mRNA expression. Gb ' cry1(RNAi) treatment had only a limited effect at the behavioral and molecular levels, while Gb ' cry2(RNAi) had a significant effect on behavioral rhythms and molecular oscillatory machinery, alone or in combination with Gb'cry1RNAi. In Gb ' cry1/ Gb ' cry2 double-RNAi crickets, most clock genes showed arrhythmic expression, except for timeless, which retained clear rhythmic expression. Molecular analysis revealed that some combination of Gb ' cry1 and Gb ' cry2 variants suppressed CLK/CYC transcriptional activity in cultured cells.Conclusion: Based on these results, we propose a new model of the cricket's circadian clock, including a molecular oscillatory loop for Gb'cry2, which can operate independent of the Gb ' per/Gb ' tim loop.

DOI： 10.1186/s40851-017-0066-7

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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  

Dickkopf-related protein 3 (Dkk3) is the third member of the Dkk gene family and identical to the gene, whose expression was reduced in immortalized cells. Therefore, its another name is reduced expression in immortalized cells. Since the intratumoral introduction of Dkk3 inhibits tumor growth in mouse models of cancers, Dkk3 is likely a tumor suppressor gene. However, the functions of Dkk3 in vivo remain unclear. As the first step to decipher the physiological roles of this gene, we examined the expression pattern of Dkk3 in various tissues from adult mice. In situ hybridization showed that Dkk3 mRNA was detected in the brain, retina, heart, gastrointestinal tract, adrenal glands, thymus, prostate glands, seminal vesicles, testes, and ovaries in a regionally specific manner. Furthermore, we raised anti-mouse Dkk3 antibody and performed immunohistochemistry. Cytoplasmic localization of Dkk3 protein was observed in the cells of the adrenal medulla, while Dkk3 immunoreactivity was observed in the lumen of the stomach and intestine, implying that the Dkk3 protein may be secreted into the lumen of the gastrointestinal tract. These results suggest that Dkk3 has pleiotropic roles for a secretory glycoprotein that acts primarily in the gastrointestinal tract, thymus, endocrine and reproductive organs of the mouse.

DOI： 10.1007/s10735-016-9703-2

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記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：Springer Japan  

The hemimetabolous insect, Gryllus bimaculatus, has two compound eyes that begin to form in the embryo and increase in size five- to sixfolds during nymphal development. Retinal stemlike cells reside in the anteroventral proliferation zone (AVPZ) of the nymphal compound eye and proliferate to increase retinal progenitors, which then differentiate to form new ommatidia in the anterior region of the eye. Here, we introduce the morphology and development of the cricket eye first, and then we focus on the roles of retinal determination genes (RDGs) such as eyes absent (eya) and sine oculis (so) in Gryllus eye formation and growth. Since the principal function of the eye is photoreception, we finally summarize opsin photopigments in this species, broadening the roles of photoreception.

DOI： 10.1007/978-4-431-56478-2_4

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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：Nature Publishing Group  

The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-Associated protein (Cas) system is a rapid gene-Targeting technology that does not require embryonic stem cells. To demonstrate dosage effects of the Pax6 gene on eye formation, we generated Pax6-deficient mice with the CRISPR/Cas system. Eyes of founder embryos at embryonic day (E) 16.5 were examined and categorized according to macroscopic phenotype as class 1 (small eye with distinct pigmentation), class 2 (pigmentation without eye globes), or class 3 (no pigmentation and no eyes). Histologically, class 1 eyes were abnormally small in size with lens still attached to the cornea at E16.5. Class 2 eyes had no lens and distorted convoluted retinas. Class 3 eyes had only rudimentary optic vesicle-like tissues or histological anophthalmia. Genotyping of neck tissue cells from the founder embryos revealed somatic mosaicism and allelic complexity for Pax6. Relationships between eye phenotype and genotype were developed. The present results demonstrated that development of the lens from the surface ectoderm requires a higher gene dose of Pax6 than development of the retina from the optic vesicle. We further anticipate that mice with somatic mosaicism in a targeted gene generated by CRISPR/Cas-mediated genome editing will give some insights for understanding the complexity in human congenital diseases that occur in mosaic form.

DOI： 10.1038/s41598-017-00088-w

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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  

Most insects show daily activity rhythms that are controlled by endogenous circadian clocks. A basic property of the clock is entrainment to daily environmental cycles to run with an exact 24-h period. The entrainment is achieved mainly through resetting by light. The present study analyses the light resetting mechanism of the clock in first-instar nymphal and adult crickets Gryllus bimaculatus (De Geer). A 3-h light pulse given at early subjective night and late subjective night causes a phase delay and an advance, respectively, of adult locomotor rhythms. The magnitude of the shift caused by the light pulse at circadian time 12 h in constant darkness is significantly smaller than that caused by a 3-h extension of light phase. Measurement of mRNA levels during the light-induced phase shifts yielded basically similar results for nymphs and adults. When a 3-h light pulse is given at early night by light phase extension, an increase of Pdp1 occurs, which is followed by upregulation of the genes Clk and subsequently by per and tim. These changes are eliminated by RNA interference of opsin-long wavelength, which is expressed in the compound eye and encodes a green-sensitive opsin, the major photoreceptor for photic entrainment of the clock. No clear changes in mRNA levels are observed for light pulses given at late subjective night or at early subjective night after 24 h of constant darkness. These results suggest that the photic entrainment mechanism of the clock may be shared by nymphal and adult crickets, including transcriptional and nontranscriptional events.

DOI： 10.1111/phen.12162

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1600612113

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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：OKAYAMA UNIV MED SCHOOL  

Human congenital anomalies provide information that contributes to the understanding of developmental mechanisms. Here we report bilateral optic nerve aplasia (ONA) with microphthalmia in the autopsy of the cadaver of a 70-year-old Japanese female. The gross anatomical inspection of the brain showed a cotton thread-like cord in the presumed location of the optic nerve tract or chiasm. Histologically, no neural retina, optic nerve bundle or retinal central vessels were formed in the eye globe, and the retinal pigment cells formed rosettes. The cornea, iris, and lens were also histologically abnormal. Immunohistochemically, no retinal cells expressed beta III tubulin, and Pax6-immunoreactive cells were present in the ciliary non-pigmented epithelial cells. This case of ONA could be attributed to the agenesis of retinal projection neurons as a sequel to the disruption of neural retina development. The neural retina formation would coordinate the proper development of ocular tissues.

DOI： 10.18926/AMO/54192

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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：NATURE PUBLISHING GROUP  

Cricket nymphs have the remarkable ability to regenerate a functional leg following amputation, indicating that the regenerating blastemal cells contain information for leg morphology. However, the molecular mechanisms that underlie regeneration of leg patterns remain poorly understood. Here, we analyzed phenotypes of the tibia and tarsus (three tarsomeres) obtained by knockdown with regeneration-dependent RNA interference (rdRNAi) against Gryllus dachshund (Gb'dac) and Distal-less (Gb'Dll). We found that depletion of Gb'Dll mRNA results in loss of the tarsal segments, while rdRNAi against Gb'dac shortens the tibia at the two most distal tarsomeres. These results indicate that Gb'Dll expression is indispensable for formation of the tarsus, while Gb'dac expression is necessary for elongation of the tibia and formation of the most proximal tarsomere. These findings demonstrate that mutual transcriptional regulation between the two is indispensable for formation of the tarsomeres, whereas Gb'dac is involved in determination of tibial size through interaction with Gb'ds/Gb'ft.

DOI： 10.1038/srep08387

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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：NATURE PUBLISHING GROUP  

What determines organ size has been a long-standing biological question. Lawrence et al. (2008) proposed the steepness hypothesis suggesting that the protocadherin Dachsous/Fat (Ds/Ft) system may provide some measure of dimension to the cells in relation to the gradient. In this paper we extended the model as a means of interpreting experimental results in cricket leg regeneration. We assumed that (1) Ds/Ft trans-heterodimers or trans-homodimers are redistributed during cell division, and (2) growth would cease when a differential of the dimer across each cell decreases to a certain threshold. We applied our model to simulate the results obtained by leg regeneration experiments in a cricket model. The results were qualitatively consistent with the experimental data obtained for cricket legs by RNA interference methodology. Using our extended steepness model, we provided a molecular-based explanation for leg size determination even in intercalary regeneration and for organ size determination.

DOI： 10.1038/srep04335

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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  

Elucidating the mechanisms underlying eye development is essential for advancing the medical treatment of eye-related disorders. The primordium of the eye is an optic vesicle (OV), which has a dual potential for generation of the developing neural retina and retinal pigment epithelium. However, the factors that regulate the differentiation of the retinal primordium remain unclear. We have previously shown that overexpression of Lhx1 and Lhx5, members of the LIM-homeobox genes, induced the formation of a second neural retina from the presumptive pigmented retina of the OV. However, the precise timing of Lhx1 expression required for neural retina differentiation has not been clarified. Moreover, RNA interference of Lhx5 has not been previously reported. Here, using a modified electroporation method, we show that, Lhx1 expression in the forebrain around stage 8 is required for neural retina formation. In addition, we have succeeded in the knockdown of Lhx5 expression, resulting in conversion of the neural retina region to a pigment vesicle-like tissue, which indicates that Lhx5 is also required for neural retina differentiation, which correlates temporally with the activity of Lhx1. These results suggest that Lhx1 and Lhx5 in the forebrain regulate neural retina differentiation by suppressing the development of the retinal pigment epithelium, before the formation of the OV.

DOI： 10.1111/dgd.12074

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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：NATURE PUBLISHING GROUP  

Hemimetabolous, or incompletely metamorphosing, insects are phylogenetically relatively basal and comprise many pests. However, the absence of a sophisticated genetic model system, or targeted gene-manipulation system, has limited research on hemimetabolous species. Here we use zinc-finger nuclease and transcription activator-like effector nuclease technologies to produce genetic knockouts in the hemimetabolous insect Gryllus bimaculatus. Following the microinjection of mRNAs encoding zinc-finger nucleases or transcription activator-like effector nucleases into cricket embryos, targeting of a transgene or endogenous gene results in sequence-specific mutations. Up to 48% of founder animals transmit disrupted gene alleles after zinc-finger nucleases microinjection compared with 17% after microinjection of transcription activator-like effector nucleases. Heterozygous offspring is selected using mutation detection assays that use a Surveyor (Cel-I) nuclease, and subsequent sibling crosses create homozygous knockout crickets. This approach is independent from a mutant phenotype or the genetic tractability of the organism of interest and can potentially be applied to manage insect pests using a non-transgenic strategy.

DOI： 10.1038/ncomms2020

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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：GENETICS SOC JAPAN  

Transcription control of multiple genes in tissue- and stage-specific patterns is still of major interest. We show here that troponin I (TNT) is expressed under the control of upstream non-coding sequences and had functions as an isoform of intermediate type between pharynx and body-wall of the gene. In Caenorhabditis elegans, three striated muscle TNIs are expressed in body-wall muscles and a cardiac isoform is expressed in the pharynx. We have analyzed the gene expression mechanisms of tni-3 gene and motility function of its protein product. Promoter deletion analysis of the tni-3 gene identified muscle enhancers including the head enhancer. The CBF1/Su(H)/LAG-1-binding motif was included in the head enhancer. Yeast one-hybrid screening isolated the lag-1 clone in five candidates. Functional differences between the three striated muscle TNIs were investigated by the expression of promoter-fusion genes into tni-2/unc-27(e155) null mutant animals. The results suggest that the cis-elements in the promoters of the three genes are important for their tissue-specific expression and that from the function of TNI-3, the tni-3 gene would be an intermediate in the evolution of these genes by gene duplication. Mechanisms of tni-3 expression and its molecular function may contribute to our understanding of gene evolution and developmental programs.

DOI： 10.1266/ggs.87.243

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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  

In the cricket Gryllus bimaculatus, a hemimetabolous insect, the compound eyes begin to form in the embryo and increase 56 fold in size during the postembryonic development of the nymphal stage. Retinal stem cells in the anteroventral proliferation zone (AVPZ) of the nymphal eye proliferate to increase retinal progenitors, which then differentiate to form new ommatidia in the anterior region of the eye. However, mechanisms underlying this type of eye formation have not been well elucidated yet. Here, we found that the homologues of the retinal determination transcription factor genes of eyes absent (eya) and sine oculis (so) are expressed during the cricket embryonic eye formation. eya is also expressed intensely in the AVPZ of the nymphal eye. To explore their functions, we performed knockdown by RNA interference (RNAi). Knockdown of Gbeya resulted in loss of the embryonic eye. In the nymphal eye, RNAi against Gbeya or Gbso impaired retinal morphology by apparently transforming cornea structures into head cuticle. These results imply that Gbeya and Gbso are essential for the differentiation of the retinal progenitor cells and maintaining retinal structures during eye development.

DOI： 10.1111/j.1440-169X.2011.01325.x

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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  

A long-standing problem of developmental biology is how body size is determined. In Drosophila melanogaster, the insulin/insulin-like growth factor (I/IGF) and target of rapamycin (TOR) signaling pathways play important roles in this process. However, the detailed mechanisms by which insect body growth is regulated are not known. Therefore, we have attempted to utilize systemic nymphal RNA interference (nyRNAi) to knockdown expression of insulin signaling components including Insulin receptor (InR), Insulin receptor substrate (chico), Phosphatase and tensin homologue (Pten), Target of rapamycin (Tor), RPS6-p70-protein kinase (S6k), Forkhead box O (FoxO) and Epidermal growth factor receptor (Egfr) and observed the effects on body size in the Gryllus bimaculatus cricket. We found that crickets treated with double-stranded RNA (dsRNA) against Gryllus InR, chico, Tor, S6k and Egfr displayed smaller body sizes, while Gryllus FoxO nyRNAi-ed crickets exhibited larger than normal body sizes. Furthermore, RNAi against Gryllus chico and Tor displayed slow growth and RNAi against Gryllus chico displayed longer lifespan than control crickets. Since no significant difference in ability of food uptake was observed between the Gryllus chico(nyRNAi) nymphs and controls, we conclude that the adult cricket body size can be altered by knockdown of expressions of Gryllus InR, chico, Tor, S6k, FoxO and Egfr by systemic RNAi. Our results suggest that the cricket is a promising model to study mechanisms underlying controls of body size and life span with RNAi methods.

DOI： 10.1111/j.1440-169X.2011.01291.x

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記述言語：英語   出版者・発行元：WILEY-BLACKWELL  

How limb size and shape is regulated is a long-standing question in developmental and regeneration biology. Recently, the protocadherin Dachsous-Fat (Ds-Ft) signaling pathway has been found to be essential for wing development of the fly and leg regeneration of the cricket. The Ds-Ft signaling pathway is linked to the Warts-Hippo (Wts-Hpo) signaling pathway, leading to cell proliferation. Several lines of evidence have suggested that the Wts-Hpo signaling pathway is involved in the control of organ size, and that this pathway is regulated by Ds-Ft and Merlin-Expanded, which are linked to morphogens such as decapentaplegic/bone morphogenic protein, Wingless/Wnt, and epidermal growth factor. Here we review recent progress in elucidating mechanisms controlling leg size and shape in insects and vertebrates, focusing on the Ds-Ft signaling pathway. We also introduce a working model, Ds-Ft steepness model, to explain how steepness of the Ds-Ft gradient controls leg size along the proximodistal axis. Developmental Dynamics 240:1028-1041, 2011. (C) 2011 Wiley-Liss, Inc.

DOI： 10.1002/dvdy.22590

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記述言語：英語   出版者・発行元：WILEY-BLACKWELL  

RNA interference (RNAi) is a cellular process by which an mRNA is targeted for degradation by a small interfering RNA that contains a strand complementary to a fragment of the target mRNA, resulting in sequence specific inhibition of gene expression. The discovery of RNAi enabled the use of loss-of-function analyses in many non-model insects other than Drosophila to elucidate the roles of specific genes. The RNAi approach has been widely used on insects in several fields, including embryogenesis, pattern formation, reproduction, biosynthesis and behavior. The increasing availability of insect genomes has made the RNAi technique an indispensable technique for characterizing gene functions in insects. Here we review the current status of RNAi-based experiments in insects and the applications of RNAi for species-specific insecticides, focusing on non-drosophilid insects. We also identify future applications for RNAi-based studies in Entomology.

DOI： 10.1111/j.1479-8298.2010.00408.x

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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：CELL PRESS  

The mode of insect embryogenesis varies among species, reflecting adaptations to different lite history strategies [1, 2]. In holometabolous insects, which include the model systems, such as the fruit fly and the red flour beetle, a large proportion of the blastoderm produces an embryo, whereas hemimetabolous embryos generally arise from a small region of the blastoderm [3]. Despite their importance in evolutionary studies, information of early developmental dynamics of hemimetabolous insects remains limited. Here, to clarify how maternal and gap gene products act in patterning the embryo of basal hemimetabolous insects, we analyzed the dynamic segmentation process in transgenic embryos of an intermediate-germ insect species, the cricket, Gryllus bimaculatus. Our data based on live imaging of fluorescently labeled embryonic cells and nuclei suggest that the positional specification of the cellular blastoderm may be established in the syncytiurn, where maternally derived gradients could act fundamentally in a way that is similar to that of Drosophila, namely throughout the egg. Then, the blastoderm cells move dynamically, retaining their positional information to form the posteriorly localized germ anlage. Furthermore, we find that the anterior head region of the cricket embryo is specified by orthodenticle in a cellular environment earlier than the gnathal and thoracic regions. Our findings imply that the syncytial mode of the early segmentation in long-germ insects evolved from a dynamic syncytial-to-cellular mode found in the present study, accompanied by a heterochronic shift of gap gene action.

DOI： 10.1016/j.cub.2010.07.044

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

DOI： 10.1016/j.mod.2009.06.799

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

DOI： 10.1016/j.mod.2009.06.797

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

DOI： 10.1016/j.mod.2009.06.666

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出版者・発行元：4  

DOI： 10.1016/j.bbapap.2007.01.003

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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：ELSEVIER SCIENCE BV  

Many repetitive elements, for example, SINEs, LINEs, LTR-retrotransposons and other SSRs are dispersed throughout eukaryotic genomes. To understand the biological function of these repetitive elements is of great current research interest. In this study, we report on the identification of a novel non-coding DNA family, designated CE1 family, in the nematode C. elegans genome. Some CE1 elements constituted a large palindrome sequence. The CE1 elements were interspersed at 95 sites in the C. elegans genome. Most of the CE1 elements were associated with, or were within, protein-coding genes. The sequence of the CE1 elements indicated that some could form a hairpin structure. One of the CE1 family, CE1 (bs258), is located in the first intron of a novel gene, C46H11.6 which encodes a PDZ/DHR/GLGF domain protein. In gfp and lacZ reporter gene assays the CE1 (bs258) element appeared to behave as an enhancer element for the expression of C46H11.6 but no effect on the expression of the opposite direction gene, pat-10 which encodes the body-wall muscle troponin C. The CE1 (bs258) RNA transcript was detected by RT-PCR even when CE1(bs258) was located in an intron. We conclude that CE1 elements are involved in the expression of adjacent genes and are therefore selectively retained in the C. elegans genome. We discussed a biological function of the CE1(bs258) having many transcription factor-binding sites. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.gene.2006.10.002

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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：BLACKWELL PUBLISHING  

The cricket Gryllus bimaculatus is a hemimetabolous insect whose nymphs posses the ability to regenerate amputated legs. Previously, we showed that Gryllus orthologues of Drosophila hedgehog (Gb'hh), wingless (Gb'wg) and decapentaplegic (Gb'dpp) are expressed during leg regeneration and play essential roles in the establishment of the proximal-distal axis. Here, we examined their roles during intercalary regeneration: when a distally amputated tibia with disparate positional values is placed next to a proximally amputated host, intercalary growth occurs in order to regenerate the missing part. In this process, we examined expression patterns of Gb'hh and Gb'wg. We found that expressions of Gb'hh and Gb'wg were induced in a regenerate and the host proximal to the amputated region, but not in the grafted donor distal to the regenerate. This directional induction occurs even in the reversed intercalation. Because these results are consistent with a distal-to-proximal respecification of the regenerate, Gb'wg may be involved in the re-establishment of the positional values in the regenerate. Furthermore, we found that no regeneration occurs when Gb'armadillo (the orthologue of beta-catenin) was knocked down by RNA interference. These results indicate that the canonical Wnt/Wingless signaling pathway is involved in the process of leg regeneration and determination of positional information in the leg segment.

DOI： 10.1111/j.1440-169x.2007.00915.x

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DOI： 10.1111/j.1365-2443.2005.00829.x

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J-GLOBAL

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J-GLOBAL

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記述言語：英語   掲載種別：書評論文，書評，文献紹介等  

Nymphs of hemimetabolous insects such as cockroaches and crickets exhibit a remarkable capacity for regenerating complex structures from damaged legs. Until recent years, however, approaches to elucidate the molecular mechanisms underlying the leg regeneration process have been lacking. Taking the cricket Gryllus bimaculatus as a model, we found that a phenotype related to regeneration frequently appears during leg regeneration, even though no phenotype is induced by RNA interference (RNAi) in the cricket nymph, designated as regeneration-dependent RNAi. Since then, we have investigated the functions of various genes encoding signaling factors and cellular adhesion proteins like Fat and Dachsous during leg regeneration. In this review, we summarize the classical knowledge about insect leg regeneration and introduce recent advances concerning the signaling cascades required for regenerating a leg. Our results provide clues to the mechanisms of regeneration which are relevant to vertebrate systems. © 2007 Birkhaueser.

DOI： 10.1007/s00018-007-7432-0

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

コオロギは、胚発生や脚形成の様式がショウジョウバエと異なる。また、コオロギ幼虫の脚は切断されても再生可能であることが知られている。コオロギの胚発生と脚再生過程に働く遺伝子の機能を解析するために、我々はRNAi法を用いている。これまでに、 embryonic, parentalそして、nymphal RNAi法を確立し、次の事を明らかにした。コオロギにおいては、(1)ショウジョウバエ(Bicoid)と異なる因子(Caudal)により、胚の前後の位置情報が与えられている可能性がある、(2)winglessシグナル伝達経路が再生過程で働いておりそして、再生過程における遠近軸に沿った位置情報の決定に関与している、(3)ヒト脆弱X症侯群の原因遺伝子のコオロギホモログfmrは、コオロギの鳴き方に影響を与える遺伝子である、(4)diphenol oxidaseをコードするlaccase 2はコオロギ外骨格の着色、硬化に関与している。

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開催年月日： 2020年3月25日 - 2020年3月27日

会議種別：ポスター発表  

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開催年月日： 2020年

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開催年月日： 2020年

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開催年月日： 2019年12月3日 - 2019年12月6日

会議種別：ポスター発表  

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開催年月日： 2019年

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開催年月日： 2019年

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開催年月日： 2018年11月28日 - 2018年11月30日

会議種別：ポスター発表  

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開催年月日： 2018年10月20日 - 2018年10月21日

会議種別：口頭発表（一般）  

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開催年月日： 2018年

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開催年月日： 2018年

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開催年月日： 2018年

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開催年月日： 2017年

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開催年月日： 2007年12月

記述言語：英語  

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開催年月日： 2007年12月

記述言語：英語  

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