| Project/Area Number |
05454025
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物生理・代謝
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| Research Institution | Joubu University (1994-1995)
University of Tsukuba (1993) |
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Principal Investigator |
WATANABE Yoshio Joubu University, Department of Commercial Sciences, Professor, 商学部, 教授 (00015918)
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| Co-Investigator(Kenkyū-buntansha) |
NUMATA Osamu University of Tsukuba, Institute of Biological Sciences, Associate Professor, 生物科学系, 助教授 (50189354)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1995: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1994: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Tetrahymena / cytoplasmic division / cell-division-arrest mutant / p85 gene / F-actin bundling factor / EF-1alpha / Ca^<2+> / calmodulin / calmodulin family protein / p85 / TCBP-25 / TCBP-23 / 分裂面決定因子 / Ca^<2+>-結合蛋白質 / テトラヒメナミオシン / small G-蛋白質 |
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| Research Abstract |
To elucidate the molecular mechanisms of cytoplasmic division in animal cells, we have mainly investigated the roles of mutant gene products of temperature-sensitive cell-division-arrest mutants (cda loci) in ciliated protozoan Tetrahymena.
Tetrahymena cdaA mutant has a defect in the detemination factor of division plane. We demonstrated that the factor was responsible not only for division plane determination but also for the formation of contractile ring microfilaments as a polymerization nucleus. The mutant gene product has been shown to be a 85 kDa protein (designated as p85). In this research period. we succeeded in cloning and sequencing of cDNA for p85. The data base analysis indicates that p85 is a new protein different from proteins known so far, but sharespartly homologous sequences with actin, EF-1alpha, Ca^<2+>/calmodulin-dependent protein kinase, suggesting that p85 is a multifunctional protein playing crucial roles in cell division.
Tetrahymena cdaC mutant is relevant to the direct mechanism of division furrow constriction and the mutant gene product has been shown to be an F-actin bundling factor. In this regard, we proved that Tetrahymena EF-1alpha has remarkable F-actin bundling activity in a physiological condition. Moreover, we demonstrated that the F-actin bundling activity was clearly regulated by Ca^<2+>/calmodulin system.
Concerning the Ca^<2+>-regulation in the constriction of contracatile ring by actomyosin system, we have investigated the functions in cell division of the threo kinds of Tetrahymena calmodulin family proteins, such as calmodulin, TCBP-25, TCBP-23, by purifying these proteins after expressing their genes in E.coli.
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