研究者詳細 - 髙橋　卓

Complexity and Conservation of Thermospermine-Responsive uORFs of SAC51 Family Genes in Angiosperms 査読

Soichi Ishitsuka, Mai Yamamoto, Minaho Miyamoto, Yoshitaka Kuwashiro, Akihiro Imai, Hiroyasu Motose, Taku Takahashi

Frontiers in Plant Science 10 2019年5月

Omeprazole Enhances Mechanical Stress-Induced Root Growth Reduction in Arabidopsis thaliana. 査読

Takashi Okamoto, Shogo Takatani, Yoshiteru Noutoshi, Hiroyasu Motose, Taku Takahashi

Plant & cell physiology 59 ( 8 ) 1581 - 1591 2018年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

Mechanical sensing is one of the most fundamental processes for sessile plants to survive and grow. The response is known to involve calcium elevation in the cell. Arabidopsis seedlings grown horizontally on agar plates covered with a dialysis membrane show a 2-fold reduction in root growth compared with those grown vertically, a response to mechanical stress generated due to gravitropism of the root. To understand the molecular mechanism of how plant roots sense and respond to mechanical stimuli, we screened chemical libraries for compounds that affect the horizontal root growth in this experimental system and found that, while having no effect on root gravitropism, omeprazole known as a proton pump inhibitor significantly enhanced the mechanical stress-induced root growth reduction especially in lower pH media. In contrast, omeprazole reversed neither the alleviation of the mechanical stress-induced growth reduction caused by calcium depletion nor the insensitivity to the mechanical stress in the ethylene signaling mutant ein2. Together with the finding that omeprazole increased expression of touch-induced genes and ETHYLENE RESPONSE FACTOR1, our results suggest that the target of omeprazole mediates ethylene signaling in the root growth response to mechanical stress.

DOI： 10.1093/pcp/pcy131

An evolutionarily conserved NIMA-related kinase directs rhizoid tip growth in the basal land plant Marchantia polymorpha. 査読国際誌

Kento Otani, Kimitsune Ishizaki, Ryuichi Nishihama, Shogo Takatani, Takayuki Kohchi, Taku Takahashi, Hiroyasu Motose

Development (Cambridge, England) 145 ( 5 ) 2018年3月

記述言語：英語

Tip growth is driven by turgor pressure and mediated by the polarized accumulation of cellular materials. How a single polarized growth site is established and maintained is unclear. Here, we analyzed the function of NIMA-related protein kinase 1 (MpNEK1) in the liverwort Marchantia polymorpha In the wild type, rhizoid cells differentiate from the ventral epidermis and elongate through tip growth to form hair-like protrusions. In Mpnek1 knockout mutants, rhizoids underwent frequent changes in growth direction, resulting in a twisted and/or spiral morphology. The functional MpNEK1-Citrine protein fusion localized to microtubule foci in the apical growing region of rhizoids. Mpnek1 knockouts exhibited increases in both microtubule density and bundling in the apical dome of rhizoids. Treatment with the microtubule-stabilizing drug taxol phenocopied the Mpnek1 knockout. These results suggest that MpNEK1 directs tip growth in rhizoids through microtubule organization. Furthermore, MpNEK1 expression rescued ectopic outgrowth of epidermal cells in the Arabidopsis thaliana nek6 mutant, strongly supporting an evolutionarily conserved NEK-dependent mechanism of directional growth. It is possible that such a mechanism contributed to the evolution of the early rooting system in land plants.

DOI： 10.1242/dev.154617

Thermospermine: An evolutionarily ancient but functionally new compound in plants 査読

Taku Takahashi

Methods in Molecular Biology 1694 51 - 59 2018年

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.

Themospermine is a structural isomer of spermine and is present in some bacteria and most of plants. An Arabidopsis mutant, acaulis5 (acl5), that is defective in the biosynthesis of thermospermine displays excessive proliferation of xylem vessels with dwarfed growth. Recent studies using acl5 and its suppressor mutants that recover the growth without thermospermine have revealed that thermospermine plays a key role in the negative control of the proliferation of xylem vessels through enhancing translation of specific mRNAs that contain a conserved upstream open-reading-frame (uORF) in the 50 leader region.

DOI： 10.1007/978-1-4939-7398-9_4

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Detection of thermospermine and spermine by HPLC in plants 査読

Taku Takahashi, Ayaka Takano, Jun-Ichi Kakehi

Methods in Molecular Biology 1694 69 - 73 2018年

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.

Thermospermine, a structural isomer of spermine, is widely spread in the plant kingdom and has recently been shown to play a key role in the repression of xylem differentiation in vascular plants. However, a standard high-performance liquid chromatography (HPLC) protocol for detecting polyamines as their dansyl derivative cannot distinguish themospermine from spermine. These isomers become separated from each other after benzoylation. In this chapter, we describe a simple protocol for extraction, benzoylation, and HPLC detection of thermospermine and spermine with other polyamines from plant material.

DOI： 10.1007/978-1-4939-7398-9_6

Scopus

Directional cell expansion requires NIMA-related kinase 6 (NEK6)-mediated cortical microtubule destabilization 査読

Shogo Takatani, Shinichiro Ozawa, Noriyoshi Yagi, Takashi Hotta, Takashi Hashimoto, Yuichiro Takahashi, Taku Takahashi, Hiroyasu Motose

SCIENTIFIC REPORTS 7 7826 2017年8月

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

Plant cortical microtubules align perpendicular to the growth axis to determine the direction of cell growth. However, it remains unclear how plant cells form well-organized cortical microtubule arrays in the absence of a centrosome. In this study, we investigated the functions of Arabidopsis NIMA-related kinase 6 (NEK6), which regulates microtubule organization during anisotropic cell expansion. Quantitative analysis of hypocotyl cell growth in the nek6-1 mutant demonstrated that NEK6 suppresses ectopic outgrowth and promotes cell elongation in different regions of the hypocotyl. Loss of NEK6 function led to excessive microtubule waving and distortion, implying that NEK6 suppresses the aberrant cortical microtubules. Live cell imaging showed that NEK6 localizes to the microtubule lattice and to the shrinking plus and minus ends of microtubules. In agreement with this observation, the induced overexpression of NEK6 reduced and disorganized cortical microtubules and suppressed cell elongation. Furthermore, we identified five phosphorylation sites in beta-tubulin that serve as substrates for NEK6 in vitro. Alanine substitution of the phosphorylation site Thr166 promoted incorporation of mutant beta-tubulin into microtubules. Taken together, these results suggest that NEK6 promotes directional cell growth through phosphorylation of beta-tubulin and the resulting destabilization of cortical microtubules.

DOI： 10.1038/s41598-017-08453-5

Editorial: Molecular Mechanisms Underlying Polyamine Functions in Plants 査読

Patrick H. Masson, Taku Takahashi, Riccardo Angelini

FRONTIERS IN PLANT SCIENCE 8 ( 14 ) 2017年1月

TLCを用いた簡便なポリアミン検出

高橋卓, 懸樋潤一, 今井章裕

ポリアミン 4 ( 1 ) 14 - 16 2017年

Thermospermine enhances translation of SAC51 and SACL1 in Arabidopsis 査読

Mai Yamamoto, Taku Takahashi

PLANT SIGNALING & BEHAVIOR 12 ( 1 ) 414 - 421 2017年

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）出版者・発行元：TAYLOR & FRANCIS INC

The excessive xylem phenotype of acaulis5 (acl5), an Arabidopsis mutant defective in the synthesis of thermospermine, indicates that thermospermine is required for negative regulation of xylem differentiation. SAC51 was identified from a dominant suppressor of acl5, sac51-d, and encodes a basic helix-loop-helix (bHLH) protein. sac51-d has a premature termination codon in one of upstream open-reading frames (uORFs) of the SAC51 mRNA that is conserved among the SAC51 family members. Thermospermine may act to bypass the inhibitory effect of the uORF on main ORF translation. Another suppressor, sac57-d, also has a mutation in the conserved uORF of SACL3, a member of the SAC51 family. On the other hand, the double knockout of SAC51 and SACL3 is insensitive to thermospermine, suggesting their key role in the response to thermospermine. However, we found that thermospermine enhances mRNA translation of SAC51 and SACL1 but not of SACL2 and SACL3. Taken together with recent findings from other groups, we propose a mechanism by which thermospermine diffused from xylem precursor cells acts non-cell-autonomously to restrict their proliferation.

DOI： 10.1080/15592324.2016.1276685

The SAC51 Family Plays a Central Role in Thermospermine Responses in Arabidopsis 査読

Qingqing Cai, Hiroko Fukushima, Mai Yamamoto, Nami Ishii, Tomoaki Sakamoto, Tetsuya Kurata, Hiroyasu Motose, Taku Takahashi

PLANT AND CELL PHYSIOLOGY 57 ( 8 ) 1583 - 1592 2016年8月

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）出版者・発行元：OXFORD UNIV PRESS

The acaulis5 (acl5) mutant of Arabidopsis thaliana is defective in the biosynthesis of thermospermine and shows a dwarf phenotype associated with excess xylem differentiation. SAC51 was identified from a dominant suppressor of acl5, sac51-d, and encodes a basic helix-loop-helix protein. The sac51-d mutant has a premature termination codon in an upstream open reading frame (uORF) that is conserved among all four members of the SAC51 family, SAC51 and SACL1-SACL3. This suggests that thermospermine cancels the inhibitory effect of the uORF in main ORF translation. Another suppressor, sac57-d, has a mutation in the conserved uORF of SACL3. To define further the function of the SAC51 family in the thermospermine response, we analyzed T-DNA insertion mutants of each gene. Although sacl1-1 may not be a null allele, the quadruple mutant showed a semi-dwarf phenotype but with an increased level of thermospermine and decreased sensitivity to exogenous thermospermine that normally represses xylem differentiation. The sac51-1 sacl3-1 double mutant was also insensitive to thermospermine. These results suggest that SAC51 and SACL3 play a key role in thermospermine-dependent negative control of thermospermine biosynthesis and xylem differentiation. Using 5' leader-GUS (beta-glucuronidase) fusion constructs, however, we detected a significant enhancement of the GUS activity by thermospermine only in SAC51 and SACL1 constructs. Furthermore, while acl5-1 sac51-1 showed the acl5 dwarf phenotype, acl5-1 sacl3-1 exhibited an extremely tiny-plant phenotype. These results suggest a complex regulatory network for the thermospermine response in which SAC51 and SACL3 function in parallel pathways.

DOI： 10.1093/pcp/pcw113

Polyamine Resistance Is Increased by Mutations in a Nitrate Transporter Gene NRT1.3 (AtNPF6.4) in Arabidopsis thaliana 査読

Wurina Tong, Akihiro Imai, Ryo Tabata, Shuji Shigenobu, Katsushi Yamaguchi, Masashi Yamada, Mitsuyasu Hasebe, Shinichiro Sawa, Hiroyasu Motose, Taku Takahashi

FRONTIERS IN PLANT SCIENCE 7 ( 834 ) 2016年6月

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）出版者・発行元：FRONTIERS MEDIA SA

Polyamines are small basic compounds present in all living organisms and act in a variety of biological processes. However, the mechanism of polyamine sensing, signaling and response in relation to other metabolic pathways remains to be fully addressed in plant cells. As one approach, we isolated Arabidopsis mutants that show increased resistance to spermine in terms of chlorosis. We show here that two of the mutants have a point mutation in a nitrate transporter gene of the NRT1/PTR family (NPF), NRT1.3 (AtNPF6.4). These mutants also exhibit increased resistance to putrescine and spermidine while loss-of-function mutants of the two closest homologs of NRT1.3, root-specific NRT1.1 (AtNPF6.3) and petiole-specific NRT1.4 (AtNPF6.2), were shown to have a normal sensitivity to polyamines. When the GUS reporter gene was expressed under the control of the NRT1.3 promoter, GUS staining was observed in leaf mesophyll cells and stem cortex cells but not in the epidermis, suggesting that NRT1.3 specifically functions in parenchymal tissues. We further found that the aerial part of the mutant seedling has normal levels of polyamines but shows reduced uptake of norspermidine compared with the wild type. These results suggest that polyamine transport or metabolism is associated with nitrate transport in the parenchymal tissue of the shoot.

DOI： 10.3389/fpls.2016.00834

Chemical control of xylem differentiation by thermospermine, xylemin, and auxin 査読

Kaori Yoshimoto, Hiroyoshi Takamura, Isao Kadota, Hiroyasu Motose, Taku Takahashi

SCIENTIFIC REPORTS 6 ( 21487 ) 2016年2月

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）出版者・発行元：NATURE PUBLISHING GROUP

The xylem conducts water and minerals from the root to the shoot and provides mechanical strength to the plant body. The vascular precursor cells of the procambium differentiate to form continuous vascular strands, from which xylem and phloem cells are generated in the proper spatiotemporal pattern. Procambium formation and xylem differentiation are directed by auxin. In angiosperms, thermospermine, a structural isomer of spermine, suppresses xylem differentiation by limiting auxin signalling. However, the process of auxin-inducible xylem differentiation has not been fully elucidated and remains difficult to manipulate. Here, we found that an antagonist of spermidine can act as an inhibitor of thermospermine biosynthesis and results in excessive xylem differentiation, which is a phenocopy of a thermospermine-deficient mutant acaulis5 in Arabidopsis thaliana. We named this compound xylemin owing to its xylem-inducing effect. Application of a combination of xylemin and thermospermine to wild-type seedlings negates the effect of xylemin, whereas co-treatment with xylemin and a synthetic proauxin, which undergoes hydrolysis to release active auxin, has a synergistic inductive effect on xylem differentiation. Thus, xylemin may serve as a useful transformative chemical tool not only for the study of thermospermine function in various plant species but also for the control of xylem induction and woody biomass production.

DOI： 10.1038/srep21487

サーモスペルミン／木部分化の鍵を握る低分子

高橋卓, 本瀬宏康

生物の科学遺伝 ( 9 ) 356 - 360 2016年

Structure, function, and evolution of plant NIMA-related kinases: Implication for phosphorylation-dependent microtubule regulation（共著）査読

S. Takatani, K. Otani, M. Kanazawa, T. Takahashi, H. Motose

J. Plant Res. 128 ( 6 ) 875 - 891 2015年11月

ATML1 and PDF2 play a redundant and essential role in Arabidopsis embryo development（共著）査読

E. Ogawa, Y. Yamada, N. Sezaki, S. Kosaka, H. Kondo, N. Kamata, M. Abe, Y. Komeda, T. Takahashi

Plant Cell Physiol. 56 ( 6 ) 1183 - 1192 2015年6月

Abscisic acid induces ectopic outgrowth in epidermal cells through cortical microtubule reorganization in Arabidopsis thaliana（共著）査読

S. Takatani, T. Hirayama, T. Hashimoto, T. Takahashi, H. Motose

Sci. Rep. 5 11364 2015年6月

Regulation and diversity of polyamine biosynthesis in plants 査読

Taku Takahashi, Wurina Tong

Polyamines: A Universal Molecular Nexus for Growth, Survival, and Specialized Metabolism 27 - 44 2015年1月

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

In higher plants, the main route for putrescine synthesis may be from arginine. Higher accumulation of putrescine under biotic and abiotic stress conditions is attributed at least in part to stress-inducible expression of arginine decarboxylase genes. Regulation of spermidine synthesis involves translational control of the S -adenosylmethionine decarboxylase mRNA, which is responsive to cellular polyamine levels. Genes encoding S -adenosylmethionine decarboxylase and spermine synthase are also responsive to environmental stimuli or show preferential expression in certain organs. Stress-inducible expression of these genes involves plant hormone signaling of abscisic acid (ABA) or methyl jasmonate (MeJA). Thermospermine synthase is widely distributed in the plant kingdom but has a unique role in the repression control of xylem differentiation in higher plants. Expression of the gene for thermospermine synthase is under negative feedback control by thermospermine. Putrescine, spermidine, and cadaverine are also essential precursors for alkaloid biosynthesis in some plant species. Polyamines occur in various aspects of plant growth as a conjugated form with cinnamic acids and proteins. Genes responsible for these conjugations have been increasingly identified.

DOI： 10.1007/978-4-431-55212-3_3

Scopus