title: Cell cycle-dependent resolution of DNA double-strand breaks.
abstract: DNA double strand breaks (DSBs) elicit prompt activation of DNA damage response (DDR), which arrests cell-cycle either in G1/S or G2/M in order to avoid entering S and M phase with damaged DNAs. Since mammalian tissues contain both proliferating and quiescent cells, there might be fundamental difference in DDR between proliferating and quiescent cells (or G0-arrested). To investigate these differences, we studied recruitment of DSB repair factors and resolution of DNA lesions induced at site-specific DSBs in asynchronously proliferating, G0-, or G1-arrested cells. Strikingly, DSBs occurring in G0 quiescent cells are not repaired and maintain a sustained activation of the p53-pathway. Conversely, re-entry into cell cycle of damaged G0-arrested cells, occurs with a delayed clearance of DNA repair factors initially recruited to DSBs, indicating an inefficient repair when compared to DSBs induced in asynchronously proliferating or G1-synchronized cells. Moreover, we found that initial recognition of DSBs and assembly of DSB factors is largely similar in asynchronously proliferating, G0-, or G1-synchronized cells. Our study thereby demonstrates that repair and resolution of DSBs is strongly dependent on the cell-cycle state.
authors.affiliation: Department of Biology, University of Naples 'Federico II', Naples, Italy.
authors.forename: Susanna
authors.initials: S
authors.lastname: Ambrosio
authors.affiliation: Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Di Palo
authors.affiliation: Department of Biology, University of Naples 'Federico II', Naples, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Napolitano
authors.affiliation: Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Amente
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.|Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy.
authors.forename: Gaetano Ivan
authors.initials: GI
authors.lastname: Dellino
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Faretta
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.|Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy.
authors.forename: Pier Giuseppe
authors.initials: PG
authors.lastname: Pelicci
authors.affiliation: Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Lania
authors.affiliation: Department of Biology, University of Naples 'Federico II', Naples, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Majello
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D001940:Breast / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000235:genetics*; D049109:Cell Proliferation; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000235:genetics*; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger
keywords: AsiSI restriction enzyme; DSB repair; cell-cycle; site-specific DSBs