题目🥩： DNA replication at the single molecule level

报告人： Prof. J.F. Allemand (巴黎高师统计物理实验室)

时间🪖： 2012年4月5日 星期四 上午10：00

地点： 闵行校区物理楼226报告厅

联系人🥗： 阮建红

摘要🤾🏼‍♀️：

We have studied DNA replication both in vivo and in vitro using single molecule techniques. In vitro we have measured the activity of polymerases on hairpin substrates in a magnetic tweezers setup. We observed a switching between polymerase and exonuclease activity that depends on the force applied on the DNA. We propose to use this observation to perform DNA sequencing. In vivo, we have implemented a fluorescence technique called detection by localization, to monitor the stoechiometry and the kinetics of DNA replication machinery in living E coli cells. We have confirmed that DNA replication of the two strands requires three polymerases and observed a regular exchange of one of the polymereases of the replication machinery and demonstrated that it is one involved in the lagging strand synthesis.Based on this observation we propose a role for the third polymerase. We also observed how the replisome is disassembled when the replicative helicase is stopped.