Xenopus Mcm10 is a CDK-substrate required for replication fork stability

Gaganmeet Singh Chadha, Agnieszka Gambus, Peter J. Gillespie, John Blow (Lead / Corresponding author)

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    Abstract

    During S phase, following activation of the S phase CDKs and the DBF4-dependent kinases (DDK), double hexamers of Mcm2-7 at licensed replication origins are activated to form the core replicative helicase. Mcm10 is one of several proteins that have been implicated from work in yeasts to play a role in forming a mature replisome during the initiation process. Mcm10 has also been proposed to play a role in promoting replisome stability after initiation has taken place. The role of Mcm10 is particularly unclear in metazoans, where conflicting data has been presented. Here, we investigate the role and regulation of Mcm10 in Xenopus egg extracts. We show that Xenopus Mcm10 is recruited to chromatin late in the process of replication initiation and this requires prior action of DDKs and CDKs. We also provide evidence that Mcm10 is a CDK substrate but does not need to be phosphorylated in order to associate with chromatin. We show that in extracts depleted of more than 99% of Mcm10, the bulk of DNA replication still occurs, suggesting that Mcm10 is not required for the process of replication initiation. However, in extracts depleted of Mcm10, the replication fork elongation rate is reduced. Furthermore, the absence of Mcm10 or its phosphorylation by CDK results in instability of replisome proteins on DNA, which is particularly important under conditions of replication stress.
    Original languageEnglish
    Pages (from-to)2183-2195
    Number of pages13
    JournalCell Cycle
    Volume15
    Issue number16
    Early online date21 Jun 2016
    DOIs
    Publication statusPublished - 2016

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    Keywords

    • Mcm10
    • Xenopus
    • DNA replication
    • CDK
    • Replication fork

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