Résumé
DNA repair by homologous recombination is highly suppressed in G1 cells to ensure that mitotic recombination occurs solely between sister chromatids. Although many homologous recombination factors are cell-cycle regulated, the identity of the events that are both necessary and sufficient to suppress recombination in G1 cells is unknown. Here we report that the cell cycle controls the interaction of BRCA1 with PALB2-BRCA2 to constrain BRCA2 function to the S/G2 phases in human cells. We found that the BRCA1-interaction site on PALB2 is targeted by an E3 ubiquitin ligase composed of KEAP1, a PALB2-interacting protein, in complex with cullin-3 (CUL3)-RBX1 (ref. 6). PALB2 ubiquitylation suppresses its interaction with BRCA1 and is counteracted by the deubiquitylase USP11, which is itself under cell cycle control. Restoration of the BRCA1-PALB2 interaction combined with the activation of DNA-end resection is sufficient to induce homologous recombination in G1, as measured by RAD51 recruitment, unscheduled DNA synthesis and a CRISPR-Cas9-based gene-targeting assay. We conclude that the mechanism prohibiting homologous recombination in G1 minimally consists of the suppression of DNA-end resection coupled with a multi-step block of the recruitment of BRCA2 to DNA damage sites that involves the inhibition of BRCA1-PALB2-BRCA2 complex assembly. We speculate that the ability to induce homologous recombination in G1 cells with defined factors could spur the development of gene-targeting applications in non-dividing cells.
| Langue d'origine | English |
|---|---|
| Pages (de-à) | 422-426 |
| Nombre de pages | 5 |
| Journal | Nature |
| Volume | 528 |
| Numéro de publication | 7582 |
| DOI | |
| Statut de publication | Published - déc. 17 2015 |
Note bibliographique
Funding Information:Acknowledgements We are grateful to R. Szilard and X.-D. Zhu for critical reading of the manuscript; to D. Lo, M. Canny and J. Young for help on the project. We also thank B. Larsen and M. Tucholska for technical support, J. Stark for the U2OS DR-GFP cells, R. Greenberg for the U2OS 256 cells, F. Sicheri for ubiquitin reagents, F. Shao for the KEAP1 bacterial expression vector and D. Cortez for USP11 cDNA. A.O. is a Scholar of the Terry Fox Foundation Strategic Training Initiative for Excellence in Radiation Research for the 21st Century (EIRR21); S.M.N. receives a postdoctoral fellowship from the Dutch Cancer Society (KWF); M.D.W. holds a long-term Human Frontier Science Program fellowship; A.S. receives an Ontario Graduate Scholarship. R.I.E. was funded by a Marie Curie postdoctoral fellowship. J.P. was supported by the Beatrice Hunter Cancer Research Institute (BHCRI) with funds provided by the Harvey Graham Cancer Research Fund as part of the Terry Fox Foundation Strategic Health Research Training Program in Cancer Research at the Canadian Institutes of Health Research (CIHR). G.D. is a Senior Scientist of the BHCRI. D.D. is the Thomas Kierans Chair in Mechanisms of Cancer Development and a Canada Research Chair (Tier 1) in the Molecular Mechanisms of Genome Integrity. Work was supported by a Grant-in-Aid from the Krembil Foundation (to D.D.) and CIHR grants FDN143343 (to D.D.) and MOP84260 (to G.D.).
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ASJC Scopus Subject Areas
- General