Excess Mcm2-7 license dormant origins of replication that can be used under conditions of replicative stress

Woodward, Anna M., Göhler, Thomas, Luciani, M. Gloria, Oehlmann, Maren, Ge, Xinquan, Gartner, Anton, Jackson, Dean A. and Blow, J Julian (2006) Excess Mcm2-7 license dormant origins of replication that can be used under conditions of replicative stress. Journal of Cell Biology, 173 (5). pp. 673-683. ISSN 0021-9525

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Abstract

In late mitosis and early G1, replication origins are licensed for subsequent use by loading complexes of the minichromosome maintenance proteins 2-7 (Mcm2-7). The number of Mcm2-7 complexes loaded onto DNA greatly exceeds the number of replication origins used during S phase, but the function of the excess Mcm2-7 is unknown. Using Xenopus laevis egg extracts, we show that these excess Mcm2-7 complexes license additional dormant origins that do not fire during unperturbed S phases because of suppression by a caffeine-sensitive checkpoint pathway. Use of these additional origins can allow complete genome replication in the presence of replication inhibitors. These results suggest that metazoan replication origins are actually comprised of several candidate origins, most of which normally remain dormant unless cells experience replicative stress. Consistent with this model, using Caenorhabditis elegans, we show that partial RNAi-based knockdown of MCMs that has no observable effect under normal conditions causes lethality upon treatment with low, otherwise nontoxic, levels of the replication inhibitor hydroxyurea.

Item Type:	Article
Faculty \ School:
Depositing User:	LivePure Connector
Date Deposited:	10 Jun 2024 15:31
Last Modified:	10 Jun 2024 15:31
URI:	https://ueaeprints.uea.ac.uk/id/eprint/95482
DOI:	10.1083/jcb.200602108

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