| Project/Area Number |
12671181
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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 |
TOMOHIKO Ohta St. Marianna University School of Medicine, Depatment of Surgery, Assistant Professor, 医学部, 講師 (60233136)
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| Co-Investigator(Kenkyū-buntansha) |
OGATA Haruki St. Marianna University School of Medicine, Depatment of Surgery, Instructor, 医学部, 助手 (60267581)
FUKUDA Mamoru St. Marianna University School of Medicine, Depatment of Surgery, Associate Professor, 医学部, 助教授 (50081724)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2001: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | breast cancer / BRCA1 / BARD1 / RING finger / ubiquitin / Ligase / ヘテロダイマー |
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| Research Abstract |
We have discovered that the BRCA1-BARD1 heterodimeric RING finger complex contains significant ubiquitin ligase activity that can be disrupted by a breast cancer-derived RING finger mutation in BRCAL While individually BRCA1 and BARD1 have very low ubiquitin ligase activities in vitro, BRCA1 combined with BARD1 exhibits dramatically higher activity. Bacterially purified RING finger domains comprising residues 1-304 of BRCA1 and residues 25-189 of BARD1 are capable of polymerizing ubiquitin. The steady state level of transfected BRCA1 in vivo was increased by co-transfection of BARD1, and reciprocally that of transfected BARD1 was increased by RRCA1, in a dose dependent manner. The breast cancer-derived, BARD1-interaction deficient mutant, BRCA1^<C61G>, does not exhibit ubiquitin ligase activity in vitro. The results suggest that the BRCA1-BARD1 complex contains an ubiquitin ligase activity that is important in prevention of breast and ovarian cancer development. Furthermore, we have mapped the residues in the RING finger domain that affect the ubiquitin ligase activity, and compared with the crystal structure of BRCA1-BARD1-UbcH5c complex to analize their binding surfaces. The results are now in preparation for publishing as collaboration with Dr. Klevit in Washington University. We have tried to identify the substrate of BRCA1-BARD1 ubiquitin ligase by protein micro sequencing of the BRCA1^<C61G>-co-immunoprecipitated proteins, although it was not successful. We plan to identify it by proteome technique next
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