| Project/Area Number |
14206015
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bioproduction chemistry/Bioorganic chemistry
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YAMAGUCHI Isomaro The University of Tokyo, Graduate School of Agriculture and Life Sciences, Professor (00012013)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAJIMA Masatoshi The University of Tokyo, Graduate School of Agriculture and Life Sciences, Assistant (50237278)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥52,260,000 (Direct Cost: ¥40,200,000、Indirect Cost: ¥12,060,000)
Fiscal Year 2004: ¥11,960,000 (Direct Cost: ¥9,200,000、Indirect Cost: ¥2,760,000)
Fiscal Year 2003: ¥14,430,000 (Direct Cost: ¥11,100,000、Indirect Cost: ¥3,330,000)
Fiscal Year 2002: ¥25,870,000 (Direct Cost: ¥19,900,000、Indirect Cost: ¥5,970,000)
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| Keywords | gibberellin / gibberellin-binding protein / gibberellin receptor / Vigna angularis / GA2-oxidase / GID1 / 受容体 / Gタンパク質 / GA 2-oxidase |
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| Research Abstract |
Gibberellin-binding protein was extracted and purified up to 200,000 folds from the cytosolic fraction of etiolated seedlings of azuki beans (Vinga angularis). The characteristics of the gibberellin-binding protein such as binding affinities for various gibberellins, reversibility of binding, and the effect of co-factors were examined. The gibberellin-binding protein specifically showed high binding affinity to GA_4, an representative active GA, while the affinity to 3-epi-GA_4, an inactive GA, was negligible, satisfying the characteristics required for gibberellin receptor(s). The effect of co-factors that Co^<2+> enhanced the binding ability to GA suggested the possibility that the gibberellin-binding protein could be a di-oxiganase such as GA2-oxidase. Three GA2-oxidase genes expressed in etiolated azuki seedlings were cloned, and their expressed proteins were subjected to the gibberellin-binding assay. One of the GA2-oxidase, VaGA2oxA1, showed high binding activity to both GA_4 and GA_9. The purified gibberellin-binding protein did not cross-reacted with anti-VaGA2oxA1-antiboy, suggesting that the gibberellin-binding protein is not a homolog of GA2-oxidases.
After OsGID1 was identified as a gibberellin receptor, the gibberellin-binding protein purified form etiolated azuki seedlings was proved to cross-react with anti-OsGID1-antibody. Thus, the gibberellin-binding protein purified from azuki etiolated seedlings is expected to be an ortholog of GID1.
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