Study of regulation of DNA replication by controlling superhelicities of single DNA molecules

2015 Fiscal Year Final Research Report

• Project/Area Number: 25650002
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Molecular biology
• Research Institution: Gunma University
• Principal Investigator: Shinji Katsura 群馬大学, 大学院理工学府, 教授 (10260598)
• Co-Investigator(Kenkyū-buntansha): Oshige Masahiko 群馬大学, 大学院理工学府, 准教授 (00451716)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: １分子観察 / DNA２次構造 / 超らせん / マグネチックツィーザー / 磁気ピンセット / 微細流路 / １本鎖DNA

Outline of Final Research Achievements

We developed an apparatus based on magnetic tweezers to introduce supercoil on a single DNA molecule, and studied the effects of negative superhelicities on the local DNA denaturation in λDNA containing the SV40 origin of DNA replication. Furthermore, we also studied the effects of superhelicities on the local denaturation in the presence of SV40 Large T antigen（SV40TAｇ）, which is an initiation protein of SV40 DNA replication,
Even in the absence of SV40TAｇ, the local denaturation of SV40ori-λDNA under a negative supercoil state was observed around the replication origin and the probability of occurrence of the local denaturation increased with negative superhelicity. Furthermore, addition of SV40TAｇ enhanced the probability of occurrence of the local denaturation and extended the single-stranded region under higher negative superhelicities.

Free Research Field

１分子生物学