| Project/Area Number |
03044111
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
NISHIMOTO Takeharu Kyusyu University, Graduate School of Medical Science, Professor, 大学院医学系研究科, 教授 (10037426)
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| Co-Investigator(Kenkyū-buntansha) |
SARRY Koronb University of Carifornia、San Diego, PostーDoct
MARY Dasso National Institute of Child Health and Human, Assistan Professor, Assistant
JOHN W Newport University of California, San Diego, Professor, Professor
NISHITANI Hideo Kyusyu University, Graduate School of Medical Science, Instructor, 大学院医学系研究科, 助手
SALLY Kornbluth University of California, San Diego, Post-Doct Fellow
NEWPORT John カリフォルニア大学, サンジエゴ分校・生物学教室, 教授
DASSO Mary カリフォルニア大学, サンジエゴ分校・生物学教室, Post―Doct
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1992: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1991: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Cell Cycle Regulation / RCC1 / GEP Activity / DNA Replication / Xenopus Egg Extract / DNA複製 / G1期停止 / Xenopus卵抽出液 / 染色体凝縮 |
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| Research Abstract |
The project was divided into two parts. The first is to prove the requirement of RCC1 protein for initiation of DNA replication. The second is to indicate that the RCC1 protein functions enzymatically rather than structurally.
1) Temperature-sensitive mutants in the RCC1 gene of BHK cells fail to maintain a correct temporal order of the cell cycle and will prematurely condense their chromosomes and enter mitosis at the restrictive temperature without having completed S phase. We have used xenopus egg extracts to investigate the role that RCC1 plays in interphase nuclear funtions and how this role might contribute to the known phenotype of temperature -sensitive RCC1 mutants. By immunodepleting RCC1 protein from egg extracts, we find that it is required for neither chromatin decondensation nor nuclear fornation but that is absolutely required for the replication of added sperm chromatin DNA. Our results further suggest that RCC1 does not participate enzynatically in replication but may b
… More
e part of a structural complex which is required for the formation or maintenance complex, the loss of RCC1 might lead directly to disruption of the regulatory system which prevents the initiation of mitosis before the completion of DNA replication.
2) The RCC1 protein has been reported that it specifically catalyse the exchange of guanine nucleotides on the Ran : ras- related nuclear protein, but not on the protein c-H-ras p21. Based on this report we confirmed that the RCC1 has a GEP activity on the Ran at first, and then ask whether the GEP function of the RCC1 is required for the initiation of DNA replication. To do this, we construct a lot of mutated RCC1 proteins according to the alanine scanning method. Those mutant without the GEP activity did not initiate sperm DNA replication, but did the mutants with the GEP function. Although our data are still preliminary, those indicate that the GEP function is required for the initiation of DNA of DNA replication. Thus, the RCC1 enzymatically functions on the cell rather than structurally. Less
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