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.