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CRL2Lrr1 promotes unloading of the vertebrate replisome from chromatin during replication termination.

ABSTRACT: A key event during eukaryotic replication termination is the removal of the CMG helicase from chromatin. CMG unloading involves ubiquitylation of its Mcm7 subunit and the action of the p97 ATPase. Using a proteomic screen in Xenopus egg extracts, we identified factors that are enriched on chromatin when CMG unloading is blocked. This approach identified the E3 ubiquitin ligase CRL2Lrr1, a specific p97 complex, other potential regulators of termination, and many replisome components. We show that Mcm7 ubiquitylation and CRL2Lrr1 binding to chromatin are temporally linked and occur only during replication termination. In the absence of CRL2Lrr1, Mcm7 is not ubiquitylated, CMG unloading is inhibited, and a large subcomplex of the vertebrate replisome that includes DNA Pol ? is retained on DNA. Our data identify CRL2Lrr1 as a master regulator of replisome disassembly during vertebrate DNA replication termination.

SUBMITTER: Dewar JM

PROVIDER: S-EPMC5358724 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature

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CRL2Lrr1 promotes unloading of the vertebrate replisome from chromatin during replication termination.

Dewar James M JM Low Emily E Mann Matthias M Räschle Markus M Walter Johannes C JC

Genes & development 20170224 3

A key event during eukaryotic replication termination is the removal of the CMG helicase from chromatin. CMG unloading involves ubiquitylation of its Mcm7 subunit and the action of the p97 ATPase. Using a proteomic screen in Xenopus egg extracts, we identified factors that are enriched on chromatin when CMG unloading is blocked. This approach identified the E3 ubiquitin ligase CRL2Lrr1, a specific p97 complex, other potential regulators of termination, and many replisome compon ...[more]

PMID: 28235849

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CRL2LRR1 is required for CMG unloading during vertebrate replication termination

Project description:A key event during eukaryotic replication termination is the removal of the CMG helicase from chromatin. CMG unloading involves ubiquitylation of its MCM7 subunit and the action of the p97 ATPase. Using a proteomic screen in Xenopus egg extracts, we identified factors that are retained on chromatin when CMG unloading is blocked and identified the E3 ubiquitin ligase CRL2LRR1 and several other potential regulators of termination including a specific p97 complex. We show that CRL2LRR1 recruitment coincides with MCM7 ubiquitylation and occurs only when replisomes converge. In the absence of CRL2LRR1, MCM7 is not ubiquitylated, CMG unloading is inhibited, and many replisome components including DNA pol are retained on DNA. Our data identify CRL2LRR1 as a master regulator of replisome disassembly during vertebrate DNA replication termination.

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