Two-component regulatory system of phosphorelay involved in cytokinin signaling

• Project/Area Number: 16370022
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 植物生理・分子
• Research Institution: KYOTO UNIVERSITY
• Principal Investigator: OKA Atsuhiro Kyoto University, Institute for Chemical Research, Professor, 化学研究所, 教授 (10093212)
• Project Period (FY): 2004 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥15,000,000 (Direct Cost: ¥15,000,000); Fiscal Year 2006: ¥3,400,000 (Direct Cost: ¥3,400,000); Fiscal Year 2005: ¥5,100,000 (Direct Cost: ¥5,100,000); Fiscal Year 2004: ¥6,500,000 (Direct Cost: ¥6,500,000)
• Keywords: Phytohormone / Cytokinin / Phosphorelay / Adaptive response / Transcription factor / Signal transduction / Two-component regulatory system / in vitro再構成実験

Research Abstract

Cytokinins are perceived in Arabidopsis by the three sensor histidine kinases (CRE1 etc.), and activate the transcription-factor type (B-type) response regulators such as ARR1. Therefore, ARR1 seemed to be functionally located downstream of CRE1. This was confirmed by the fact that ARR1 activation suppresses the defects of CRE1 in the absence of cytokinin. Biochemical study in vitro showed that CRE1 is capable of autophosphorylation followed by transfer of its phosphoryl group to ARR1 via HPt intervening factors (AHPs), mimicking prokaryotic His-Asp phosphorelay. We searched, in a genome-wide scale, genes targeted directly by ARR1, and identified various genes that code for A-type response regulators, transcription factors, cytokinin-catabolising enzymes, and pathogen-wounding response proteins. The majority of these identified targets were genes whose expression are immediately and primarily induced by cytokinin. Contribution of ARR1 to the respective target genes varied significantly, indicating that the B-type response regulators are functionally overlapping with each other but have some preference for the respective target genes. These results implied that the majority of immediately and primarily cytokinin-responsive genes are activated by the His-Asp phosphorelay system consisting of CRE1 and ARR1, and that no other regulatory system is involved in cytokinin signaling in Arabidopsis. Furthermore, suppression experiments of CRE1 defects led to the identification of a pseudo-AHP gene (AHP6). AHP6 contributed toward the regulation of cell fate during root vascular development by inhibiting cytokinin signaling. Since this inhibition is thought to occur by competing with AHPs, the view of AHP intervention between CRE1 and ARR1 was further strengthened in vivo.

Research Products

• [Journal Article] ARR1 directly activates cytokinin response genes that encode proteins with diverse regulatory functions. (2007)
  • Author(s): Taniguchi, M., Sasaki, N., Tsuge, T., Aoyama, T., Oka A.
  • Journal Title: Plant Cell. Physiol. 48・2 Pages: 263-277
  • NAID: 10018519460
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] ARR1 directly activates cytokinin response genes that encode proteins with diverse regulatory functions. (2007)
  • Author(s): Taniguchi, M., Sasaki, N., Tsuge, T., Aoyama, T., Oka A.
  • Journal Title: Plant Cell. Physiol. 48(2) Pages: 263-277
  • NAID: 10018519460
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] ARR1 directly activates cytokinin response genes that encode proteins with diverse regulatory functions. (2007)
  • Author(s): Taniguchi, M., Sasaki, N., Tsuge, T., Aoyama, T., Oka A.
  • Journal Title: Plant Cell Physiol. 48(2) Pages: 263-277
  • NAID: 10018519460
• [Journal Article] The A-type cyclin CYCA2;3 is a key regulator of ploidy levels in Arabidopsis endreduplication. (2006)
  • Author(s): Imai, K., Ohashi, Y., Tsuge, T., Yoshizumi, T., Matsui, M., Oka, A., Aoyama, T.
  • Journal Title: Plant Cell 18・2 Pages: 382-396
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development. (2006)
  • Author(s): Mahonen, A.P., Bishopp, A., Higuchi, M., Nieminen, K.M., Kinoshita, K., Tormakangas, K., Ikeda, Y., Oka, A., Kakimoto, T., Helariutta, Y.
  • Journal Title: Science 311・5757 Pages: 94-98
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] The A-type cyclin CYCA2;3 is a key regulator of ploidy levels in Arabidopsis endreduplication (2006)
  • Author(s): Imai, K., Ohashi, Y., Tsuge, T., Yoshizumi, T., Matsui, M., Oka, A., Aoyama, T..
  • Journal Title: Plant Cell 18(2) Pages: 382-396
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development. (2006)
  • Author(s): Mahonen, A.P., Bishopp, A., Higuchi, M., Nieminen, KM., Kinoshita, K., Tormakangas, K, Ikeda, Y., Oka, A., Kakimoto, T., Helariutta, Y.
  • Journal Title: Science 311(5757) Pages: 94-98
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] The A-type cyclin CYCA2;3 is a key regulator of ploidy levels in Arabidopsis endreduplication. (2006)
  • Author(s): Imai, K., Ohashi, Y., Tsuge, T., Yoshizumi, T., Matsui, M., Oka, A., Aoyama, T.
  • Journal Title: Plant Cell 18(2) Pages: 382-396
• [Journal Article] Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development. (2006)
  • Author(s): Mahonen, A.P., Bishopp, A., Higuchi, M., Nieminen, K.M., Kinoshita, K., Tormakangas, K., Ikeda, Y., Oka, A., Kakimoto, T., Helariutta, Y.
  • Journal Title: Science 311 Pages: 94-98
• [Journal Article] The A-type cyclin CYCA2;3 is a key regulator of ploidy levels in Arabidopsis endreduplication. (2006)
  • Author(s): Imai, K., Ohashi, Y., Tsuge, T., Yoshizumi, T., Matsui, m., Oka, A., Aoyama, T.
  • Journal Title: Plant Cell 18(2) Pages: 382-396
• [Journal Article] 植物の光情報伝達の解明はがん治療に役立つか-COP9シグナロソーム研究の最前線 (2005)
  • Author(s): 柘植知彦, 岡 穆宏
  • Journal Title: 化学 60・11 Pages: 72-73
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Will the research in plant light signaling contribute to the cure of cancer?-The frontier research of COP9 signalosome (2005)
  • Author(s): Tsuge, T., Oka, A.
  • Journal Title: Kagaku(in Japanese) 60(11) Pages: 72-73
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] 植物の光情報伝達の解明はがん治療に役立つか---COP9シグナロソーム研究の最前線 (2005)
  • Author(s): 拓殖知彦, 岡 穆宏
  • Journal Title: 化学 60(11) Pages: 72-73
• [Journal Article] サイトカイニン応答 (2004)
  • Author(s): 柿本辰男, 岡 穆宏
  • Journal Title: 植物の環境応答と形態形成のクロストーク (Springer) Pages: 123-130
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] シロイヌナズナのHis-Aspリン酸リレー制御系 (2004)
  • Author(s): 岡 穆宏
  • Journal Title: 植物の環境応答と形態形成のクロストーク (Springer) Pages: 143-151
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Adaptive responses to cytokinins of plants (2004)
  • Author(s): Kakimoto, T., Oka, A.
  • Journal Title: Crosstalk between adaptive responses to environmental stimuli and morphogenesis in plants(in Japanese)(Springer-Verlag) Pages: 123-130
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] His-Asp phosphorelay signal transduction in Arabidopsis thaliana. (2004)
  • Author(s): Oka, A.
  • Journal Title: Crosstalk between adaptive responses to environmental stimuli and morphogenesis in plants(in Japanese)(Springer-Verlag) Pages: 143-151
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] サイトカイニン応答 (2004)
  • Author(s): 柿本辰男
  • Journal Title: 植物の環境応答と形態形成のクロストーク Pages: 123-130
• [Journal Article] シロイヌナズナのHis-Aspリン酸リレー制御系 (2004)
  • Author(s): 岡 穆宏
  • Journal Title: 植物の環境応答と形態形成のクロストーク Pages: 143-151
• [Journal Article] Contribution of phospholipase D to morphogenesis of plant epidermal cells. (2004)
  • Author(s): Oka, A.
  • Journal Title: Genes & Genetic Systems 79・6 Pages: 377-377
• [Book] 植物の環境応答と形態形成のクロストーク (2004)
  • Author(s): (編集)岡 穆宏
  • Total Pages: 230
  • Publisher: Springer Verlag, Tokyo