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RAD51- and MRE11-dependent reassembly of uncoupled CMG helicase complex at collapsed replication forks.

ABSTRACT: In 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 ? 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.

SUBMITTER: Hashimoto Y

PROVIDER: S-EPMC4306020 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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RAD51- and MRE11-dependent reassembly of uncoupled CMG helicase complex at collapsed replication forks.

Hashimoto Yoshitami Y Puddu Fabio F Costanzo Vincenzo V

Nature structural & molecular biology 20111204 1

In 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 ...[more]

PMID: 22139015

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