| Project/Area Number |
15570057
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphology/Structure
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| Research Institution | National Institute for Basic Biology (2004)
Okazaki National Research Institutes (2003) |
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Principal Investigator |
MURATA Takashi National Institute for Basic Biology, Division of Evolutionary Biology, Associate Professor, 生物進化研究部門, 助教授 (00242024)
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| Co-Investigator(Kenkyū-buntansha) |
HASEBE Mitsuyasu National Institute for Basic Biology, Division of Evolutionary Biology, Professor, 生物進化研究部門, 教授 (40237996)
FUJITA Tomomichi National Institute for Basic Biology, Division of Evolutionary Biology, Assistant Professor, 生物進化研究部門, 助手 (50322631)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | cortical microtubule / gamma-tubulin / microtubule organizing center / tobacco BY-2 cells / 微小管 / 植物細胞 |
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| Research Abstract |
Despite the absence of a conspicuous microtubule organizing center, microtubules in interphase plant cells are present in the cell cortex as a well oriented array. By the support of the Grant-in-Aid for Scientific Research, we show that nucleation requires extant cortical microtubules, onto which cytosolic γ-tubulin is recruited. Microtubule-independent nucleation is rarely observed in living tobacco BY-2 cells and nucleation is minimal in the absence of original microtubules in a cell-free system. In both living cells and the cell-free system, microtubules are nucleated as branches on the extant cortical microtubules. The branch points contain γ-tubulin, which is abundant in the cytoplasm, and microtubule nucleation in the cell free system is prevented by inhibiting γ-tubulin function with specific antibodies. When isolated plasma membrane with microtubules is exposed to purified neuro-tubulin, no microtubules are nucleated, but when the membrane is exposed to a cytosolic extract, γ-tubulin binds microtubules on the membrane, and after a subsequent incubation in neuro-tubulin, microtubules are nucleated on the pre-existing microtubules. We propose that a cytoplasmic γ-tubulin complex shuttles between cytoplasm and the side of a cortical microtubule and has nucleation activity only when bound to the microtubule.
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