2017 Fiscal Year Final Research Report
Direct single-molecule observations of DNA unwinding by SV40 large tumor antigen under a negative DNA supercoil state
| Project/Area Number |
15K06946
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Molecular biology
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| Research Institution | Gunma University |
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Principal Investigator |
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| Project Period (FY) |
2015-10-21 – 2018-03-31
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| Keywords | DNA / DNA複製 / 高次構造 / 超らせん / SV40 / １分子観察 |
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| Outline of Final Research Achievements |
Superhelices, which are induced by the twisting and coiling of double-helical DNA in chromosomes, are thought to affect DNA metabolic processes. In this study, I report the effects of negative supercoiling on the unwinding activity of simian virus 40 large tumor antigen (SV40 TAg) at a single-molecular level. The supercoiling density of linear DNA templates was controlled using magnetic tweezers and monitored using a fluorescent microscope in a flow cell. SV40 TAg-mediated DNA unwinding under relaxed and negative supercoil states was analyzed by the direct observation of both single- and double-stranded regions of single DNA molecules. Increased negative superhelicity stimulated SV40 TAg-mediated DNA unwinding more strongly than a relaxed state; furthermore, negative superhelicity was associated with an increased probability of SV40 TAg-mediated DNA unwinding. These results suggest that negative superhelicity helps to regulate the initiation of DNA replication.
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| Free Research Field |
分子生物
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