| Project/Area Number |
16370079
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Molecular biology
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| Research Institution | HOKKAIDO UNIVERSITY (2006)
Kyoto University (2004-2005) |
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Principal Investigator |
OBUSE Chikashi Hokkaido Univ., Faculty of Advanced Life Science, Prof., 大学院先端生命科学研究院, 教授 (00273855)
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| Co-Investigator(Kenkyū-buntansha) |
柳田 充弘 京都大学, 大学院・生命科学研究科, 教授 (80025428)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2006: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2005: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 2004: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | chromatin / replication / heterochromatin / ORC / telomere / mass spectrometry / proteomics / cell cycle / 染色体分配 / RNAi / 複製開始点 / 動原体 / 複製 / 染色体 / 分配 / HP1 / セントロメア |
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| Research Abstract |
ORC (Origin Recognition comple) is conserved among eukaryote, and essential for initiation of chromosomal replication. Recent studies suggest that ORC is involved in other cellular function, such as translation, chromosome segregation and cytokinesis, This research is aimed to uncover the molecular link between ORC and these cellular function other than chromosomal replication in human cells by proteomic approach.
Analysis of imunoprecipitates with ORC1 by proteomic approach using mass spectrometry found that ORC1 associates with ORC2, ORC3, ORC4 and ORC5. In addition to ORC subunits, it was revealed that constituents of telomere (TRF2, Rap 1), nuclear membrane (Sadl/Unc84) and uncharacterized WD40 protein (designated as ORC1BP1).
In relation to TRF2, it directly associates with ORC1 through myb-domain. This research showed that ORC and TRF2 interact with each other to achieve stable binding to telomere repeat. Knock down of ORC1 level by specific RNA interference induce telomere elongation, suggesting that ORC is involved in telomere homeostasis in human cells.
In relation to ORC1BP1, ORC1BP1 has Leu-rich repeat at its N-terminal half and WD40 repeat at its N-terminal half. This research showed that ORC1BP1 localized in nuclei and tightly associates with ORC1 and ORC2. Inhibition of ORC1BP1 by RNA interference cause prolonged period of G1 phase, indicated by reduction of BrdU and Cyclin B positive cells and increase of CDT1 positive cells. These results suggest that ORC1BP1 involved in G1 progression through direct interaction with ORC complex.
As described above, we could show some molecular links having ORC as its pivot which might be clues about explanation for ORC function in chromosome segregation and cycotkinesis.
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