Tight Chk1 Levels Control Replication Cluster Activation in Xenopus

• DOI: 10.1371/journal.pone.0129090
• Publication Date: 2015-06-05T19:17:11Z
• Authors: Marie Platel; Arach Goldar; Jennifer M. Wiggins; Pedro Barbosa; Pierre Libeau; Pierre Priam; Hemalatha Narassi...; Xenia Grodzenski; Kathrin Marheineke
• Keywords: Replication factor C; Licensing factor; Replication; Origin recognition complex; Replication timing; CHEK1

DNA replication in higher eukaryotes initiates at thousands of origins according to a spatio-temporal program. The ATR/Chk1 dependent checkpoint inhibits the activation later firing origins. In Xenopus vitro system initiations are not sequence and 2-5 grouped clusters that fire different times despite very short S phase. We have shown temporal program is stochastic level single clusters. It unclear how late but permits origin early Here, we analyze role Chk1 sperm nuclei replicating egg extracts by combination experimental modelling approaches. After inhibition or immunodepletion, observed an increase extent fork density presence absence external stress. However, overexpression stress inhibited decreasing densities due lower Cdk2 kinase activity. Thus, levels need be tightly controlled order properly regulate even during normal combing experiments showed outside, inside, already active Numerical simulations initiation frequencies activity consistent with global combined local repression action close activated fit our data.