CtIP-mediated resection is essential for viability and can operate independently of BRCA1
| Autor: | Michael J. Kruhlak, Richard Baer, Lionel Feigenbaum, Stephen P. Jackson, Robert B. Faryabi, Nancy Wong, Federica Polato, Thomas Ludwig, Hua Tang Chen, Samuel F. Bunting, Colleen R. Reczek, Elsa Callen, André Nussenzweig, Marina L. Kozak, Wen-Hwa Lee |
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| Rok vydání: | 2014 |
| Předmět: |
Genome instability
endocrine system diseases DNA Repair DNA repair Cell Survival Chromosomal Proteins Non-Histone Poly ADP ribose polymerase Immunology Mutant Immunoblotting Cell Cycle Proteins Mice Transgenic Poly(ADP-ribose) Polymerase Inhibitors DNA-binding protein Genomic Instability 03 medical and health sciences chemistry.chemical_compound Mice 0302 clinical medicine Immunology and Allergy Animals DNA Breaks Double-Stranded Enzyme Inhibitors skin and connective tissue diseases Homologous Recombination Cells Cultured 030304 developmental biology Cell Proliferation Mice Knockout 0303 health sciences B-Lymphocytes Microscopy Confocal biology BRCA1 Protein Brief Definitive Report Helicase Molecular biology Cell biology DNA-Binding Proteins chemistry 030220 oncology & carcinogenesis Mutation biology.protein Poly(ADP-ribose) Polymerases Homologous recombination Carrier Proteins Tumor Suppressor p53-Binding Protein 1 DNA Protein Binding |
| Zdroj: | The Journal of Experimental Medicine |
| ISSN: | 1540-9538 |
| Popis: | In contrast to BRCA1, CtIP has indispensable roles in promoting resection and embryonic development. Homologous recombination (HR) is initiated by DNA end resection, a process in which stretches of single-strand DNA (ssDNA) are generated and used for homology search. Factors implicated in resection include nucleases MRE11, EXO1, and DNA2, which process DNA ends into 3′ ssDNA overhangs; helicases such as BLM, which unwind DNA; and other proteins such as BRCA1 and CtIP whose functions remain unclear. CDK-mediated phosphorylation of CtIP on T847 is required to promote resection, whereas CDK-dependent phosphorylation of CtIP-S327 is required for interaction with BRCA1. Here, we provide evidence that CtIP functions independently of BRCA1 in promoting DSB end resection. First, using mouse models expressing S327A or T847A mutant CtIP as a sole species, and B cells deficient in CtIP, we show that loss of the CtIP-BRCA1 interaction does not detectably affect resection, maintenance of genomic stability or viability, whereas T847 is essential for these functions. Second, although loss of 53BP1 rescues the embryonic lethality and HR defects in BRCA1-deficient mice, it does not restore viability or genome integrity in CtIP−/− mice. Third, the increased resection afforded by loss of 53BP1 and the rescue of BRCA1-deficiency depend on CtIP but not EXO1. Finally, the sensitivity of BRCA1-deficient cells to poly ADP ribose polymerase (PARP) inhibition is partially rescued by the phospho-mimicking mutant CtIP (CtIP-T847E). Thus, in contrast to BRCA1, CtIP has indispensable roles in promoting resection and embryonic development. |
| Databáze: | OpenAIRE |
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