Liu, Yang, Wang, Lu, Xu, Xin, Yuan, Yue, Zhang, Bo, Li, Zeyang, Xie, Yuchen, Yan, Rui, Zheng, Zeqi, Ji, Jianguo, Murray, Johanne M, Carr, Antony M and Kong, Daochun (2021) The intra-S phase checkpoint directly regulates replication elongation to preserve the integrity of stalled replisomes. Proceedings of the National Academy of Sciences (PNAS), 118 (24). a2019183118. ISSN 0027-8424

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Abstract

DNA replication is dramatically slowed down under replication stress. The regulation of replication speed is a conserved response in eukaryotes and, in fission yeast, requires the checkpoint kinases Rad3ATR and Cds1Chk2 However, the underlying mechanism of this checkpoint regulation remains unresolved. Here, we report that the Rad3ATR-Cds1Chk2 checkpoint directly targets the Cdc45-MCM-GINS (CMG) replicative helicase under replication stress. When replication forks stall, the Cds1Chk2 kinase directly phosphorylates Cdc45 on the S275, S322, and S397 residues, which significantly reduces CMG helicase activity. Furthermore, in cds1
Chk2
-mutated cells, the CMG helicase and DNA polymerases are physically separated, potentially disrupting replisomes and collapsing replication forks. This study demonstrates that the intra-S phase checkpoint directly regulates replication elongation, reduces CMG helicase processivity, prevents CMG helicase delinking from DNA polymerases, and therefore helps preserve the integrity of stalled replisomes and replication forks.

Item Type:	Article
Keywords:	CMG complex, checkpoint, replication fork stability
Schools and Departments:	School of Life Sciences > Sussex Centre for Genome Damage and Stability
SWORD Depositor:	Mx Elements Account
Depositing User:	Mx Elements Account
Date Deposited:	14 Jun 2021 08:13
Last Modified:	26 Apr 2023 08:39
URI:	http://sro.sussex.ac.uk/id/eprint/99761

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