Cdk1 uncouples CtIP-dependent resection and Rad51 filament formation during M-phase double-strand break repair

• Published in: The Journal of cell biology Vol. 194; no. 5; pp. 705 - 720
• Main Authors: Peterson, Shaun E, Li, Yinyin, Chait, Brian T, Gottesman, Max E, Baer, Richard, Gautier, Jean
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 05.09.2011; The Rockefeller University Press
• Subjects: Animals; Antigens, Nuclear - metabolism; Ataxia Telangiectasia Mutated Proteins; CDC2 Protein Kinase - antagonists & inhibitors; CDC2 Protein Kinase - metabolism; Cell Cycle Proteins - metabolism; Cell Division - physiology; Cell Nucleus - metabolism; Cell-Free System; Cells; Checkpoint Kinase 1; Chromatin - metabolism; Cyclin-Dependent Kinase 2 - antagonists & inhibitors; Cyclin-Dependent Kinase 2 - metabolism; Deoxyribonucleic acid; DNA; DNA Breaks, Double-Stranded; DNA Helicases - metabolism; DNA repair; DNA Repair - physiology; DNA, Single-Stranded - metabolism; DNA-Binding Proteins - metabolism; Endonucleases - metabolism; HeLa Cells; Histones - metabolism; Humans; Ku Autoantigen; Meiosis - physiology; Mitosis - physiology; MRE11 Homologue Protein; Nuclear Envelope - physiology; Ovum; Phosphorylation; Phosphorylation - drug effects; Protein Binding - drug effects; Protein Binding - physiology; Protein Kinase Inhibitors - pharmacology; Protein Kinases - metabolism; Protein-Serine-Threonine Kinases - metabolism; Rad51 Recombinase - metabolism; RecQ Helicases - metabolism; Replication Protein A - metabolism; S Phase - physiology; Tumor Suppressor Proteins - metabolism; Vertebrates; Werner Syndrome Helicase; Xenopus laevis; Xenopus Proteins - antagonists & inhibitors; Xenopus Proteins - metabolism
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.201103103

DNA double-strand break (DSB) resection, which results in RPA-bound single-stranded DNA (ssDNA), is activated in S phase by Cdk2. RPA-ssDNA activates the ATR-dependent checkpoint and homology-directed repair (HDR) via Rad51-dependent mechanisms. On the other hand, the fate of DSBs sustained during vertebrate M phase is largely unknown. We use cell-free Xenopus laevis egg extracts to examine the recruitment of proteins to chromatin after DSB formation. We find that S-phase extract recapitulates a two-step resection mechanism. M-phase chromosomes are also resected in cell-free extracts and cultured human cells. In contrast to the events in S phase, M-phase resection is solely dependent on MRN-CtIP. Despite generation of RPA-ssDNA, M-phase resection does not lead to ATR activation or Rad51 chromatin association. Remarkably, we find that Cdk1 permits resection by phosphorylation of CtIP but also prevents Rad51 binding to the resected ends. We have thus identified Cdk1 as a critical regulator of DSB repair in M phase. Cdk1 induces persistent ssDNA-RPA overhangs in M phase, thereby preventing both classical NHEJ and Rad51-dependent HDR.