Nat Struct Mol Biol. January 1, 2012; 19 (1):
RAD51- and MRE11-dependent reassembly of uncoupled CMG helicase complex at collapsed replication forks.
Hashimoto Y , Puddu F , Costanzo V .
AbstractIn higher eukaryotes, the dynamics of replisome components during fork collapse and restart are poorly understood. Here we have reconstituted replication fork collapse and restart by inducing single-strand DNA lesions that create a double-strand break in one of the replicated sister chromatids after fork passage. We found that, upon fork collapse, the active CDC45-MCM-GINS (CMG) helicase complex loses its GINS subunit. A functional replisome is restored by the reloading of GINS and polymerase ɛ onto DNA in a fashion that is dependent on RAD51 and MRE11 but independent of replication origin assembly and firing. PCNA mutant alleles defective in break-induced replication (BIR) are unable to support restoration of replisome integrity. These results show that, in higher eukaryotes, replisomes are partially dismantled after fork collapse and fully re-established by a recombination-mediated process.
Pubmed Id: 22139015Article link:
Cancer Research UK