The dynamics of replication licensing in live Caenorhabditis elegans embryos

Sonneville, Remi, Querenet, Matthieu, Craig, Ashley, Gartner, Anton and Blow, J. Julian (2012) The dynamics of replication licensing in live Caenorhabditis elegans embryos. Journal of Cell Biology, 196 (2). pp. 233-246. ISSN 0021-9525

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Abstract

Accurate DNA replication requires proper regulation of replication licensing, which entails loading MCM-2-7 onto replication origins. In this paper, we provide the first comprehensive view of replication licensing in vivo, using video microscopy of Caenorhabditis elegans embryos. As expected, MCM-2-7 loading in late M phase depended on the prereplicative complex (pre-RC) proteins: origin recognition complex (ORC), CDC-6, and CDT-1. However, many features we observed have not been described before: GFP-ORC-1 bound chromatin independently of ORC-2-5, and CDC-6 bound chromatin independently of ORC, whereas CDT-1 and MCM-2-7 DNA binding was interdependent. MCM-3 chromatin loading was irreversible, but CDC-6 and ORC turned over rapidly, consistent with ORC/CDC-6 loading multiple MCM-2-7 complexes. MCM-2-7 chromatin loading further reduced ORC and CDC-6 DNA binding. This dynamic behavior creates a feedback loop allowing ORC/CDC-6 to repeatedly load MCM-2-7 and distribute licensed origins along chromosomal DNA. During S phase, ORC and CDC-6 were excluded from nuclei, and DNA was overreplicated in export-defective cells. Thus, nucleocytoplasmic compartmentalization of licensing factors ensures that DNA replication occurs only once.

Item Type:	Article
Faculty \ School:
Depositing User:	LivePure Connector
Date Deposited:	10 Jun 2024 15:31
Last Modified:	06 Feb 2025 11:59
URI:	https://ueaeprints.uea.ac.uk/id/eprint/95473
DOI:	10.1083/jcb.201110080

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