| Project/Area Number |
18591445
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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 |
General surgery
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| Research Institution | St.Marianna University School of Medicine |
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Principal Investigator |
FUKUDA Mamoru St.Marianna University School of Medicine, Department of Surgery, Professor (50081724)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥4,010,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥510,000)
Fiscal Year 2007: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | BRCA1 / BARD1 / familial breast cancer / ubiquitin ligase / HERC2 / 2D-DIGE / proteomics |
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| Research Abstract |
Analyses for regulation of protein stability of breast tumor suppressor BRCA1 is important to understand the mechanisms underlying breast carcinogenesis. The purposes of the project were as following: 1) Screen of substrates ubiquitinated by BRCA1 or of factors that regulates BRCA1. 2) Functional analyses of HERC2-mediated regulation of BRCA1. 3) Phenotypic analyses of HERC2 transgenic mice. Results: 1) Rabbit polyclonal antibodies to BRCA1 were generated to immunoprecipitate large amounts of BRCA1 complexes. However, I could not identify any novel factors that regulates or were regulated by BRCA1 using the screens. 2) The interaction between endogenous HERC2 and BRCA1 was confirmed by immunoprecipitation followed by immunoblotting. HERC2-BRCA1 interaction in cells maximized in the S phase of the cell cycle, when the BRCA1 expression minimized. Fragment analyses revealed that C-terminus of HERC2 that contains HECT domain interacts with N-terminal degron domain of BRCA1. Endogenous HERC2 mainly localized in the cytoplasm and was imported to the nuclear by the Crm1 inhibitor leptomycin B, suggesting that HERC2 was a cytoplasmic and nuclear shuttle protein. These data suggest that HERC2 is a possible E3 ligase for BRCA1 that targets BRCA1 for degradation in S phase. 3) We obtained 13 clones of transgenic mice and selected mice that expressed mRNA of HERC2 C-terminus in the breast tissue under MMTV induction. However, no significant phenotype was observed.
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