|2020年11月5日（星期四）上午10:00 生科楼2018会议室：DNA replication termination in C. elegans|
题目：DNA replication termination in C. elegans
报告人：Dr. Yisui Xia（夏乙燧） University of Dundee, UK.
09/2009 – 10/2016 Ph.D. College of Biological Sciences, China Agricultural University
10/2016 – Present Postdoctoral researcher in MRC PPU, Dundee University
The core of replisome is replicative helicase CMG complex, which in turn is formed by the six Mcm2-7 ATPases, the Cdc45 protein, and the GINS complex (CMG = Cdc45-MCM-GINS). The CMG complex remains associated tightly with replication forks throughout replication elongation since it can’t be re-assembled. This remarkably stable association of CMG with replication forks implies a particular mechanism is required to unload this helicase and trigger replisome disassembly during DNA replication termination, which also means the disassembly of CMG is the primary step of unloading the replicative machinery from the chromosome when replication is finished.
CMG disassembly is initiated by ubiquitylation of Mcm7 subunit of hexamer ATPase, leading rapidly to a disassembly reaction that requires Cdc48 (also known as p97) AAA+ ATPase ‘unfoldase’ with its main-adaptors Npl4 and Ufd1.
I am going to show how CUL-2LRR-1 is regulated during DNA replication termination by using both in vivo and in vitro approaches. Especially, we reconstituted worm CMG ubiquitylation and following step disassembly by purified protein in vitro, which reveals the molecular mechanism of CMG ubiquitylation and disassembly during replication termination.