A conserved Polϵ binding module in Ctf18-RFC is required for S-phase checkpoint activation downstream of Mec1

Luis J. García-Rodríguez, Giacomo De Piccoli, Vanessa Marchesi, Richard C. Jones, Ricky D. Edmondson, Karim Labib (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)
162 Downloads (Pure)

Abstract

Defects during chromosome replication in eukaryotes activate a signaling pathway called the S-phase checkpoint, which produces a multifaceted response that preserves genome integrity at stalled DNA replication forks. Work with budding yeast showed that the ‘alternative clamp loader’ known as Ctf18-RFC acts by an unknown mechanism to activate the checkpoint kinase Rad53, which then mediates much of the checkpoint response. Here we show that budding yeast Ctf18-RFC associates with DNA polymerase epsilon, via an evolutionarily conserved ‘Pol ϵ binding module’ in Ctf18-RFC that is produced by interaction of the carboxyl terminus of Ctf18 with the Ctf8 and Dcc1 subunits. Mutations at the end of Ctf18 disrupt the integrity of the Pol ϵ binding module and block the S-phase checkpoint pathway, downstream of the Mec1 kinase that is the budding yeast orthologue of mammalian ATR. Similar defects in checkpoint activation are produced by mutations that displace Pol ϵ from the replisome. These findings indicate that the association of Ctf18-RFC with Pol ϵ at defective replication forks is a key step in activation of the S-phase checkpoint.
Original languageEnglish
Pages (from-to)8830-8838
JournalNucleic Acids Research
Volume43
Issue number18
Early online date6 Aug 2015
DOIs
Publication statusPublished - 15 Oct 2015

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