title: Impact of the KU80 pathway on NHEJ-induced genome rearrangements in mammalian cells.
abstract: Using a substrate measuring deletion or inversion of an I-SceI-excised fragment and both accurate and inaccurate rejoining, we determined the impact of non-homologous end-joining (NHEJ) on mammalian chromosome rearrangements. Deletion is 2- to 8-fold more efficient than inversion, independent of the DNA ends structure. KU80 controls accurate rejoining, whereas in absence of KU mutagenic rejoining, particularly microhomology-mediated repair, occurs efficiently. In cells bearing both the NHEJ and a homologous recombination (HR) substrate containing a third I-SceI site, we show that NHEJ is at least 3.3-fold more efficient than HR, and translocation of the I-SceI fragment from the NHEJ substrate locus into the HR-I-SceI site can occur, but 50- to 100-fold less frequently than deletion. Deletions and translocations show both accurate and inaccurate rejoining, suggesting that they correspond to a mix of KU-dependent and KU-independent processes. Thus these processes should represent prominent pathways for DSB-induced genetic instability in mammalian cells.
authors.affiliation: UMR CNRS/CEA 217, Laboratoire d'étude des Mécanismes de la Recombinaison, Direction des Sciences du vivant, Département de Radiobiologie et Radiopathologie, 18 route du Panorama, 92265 Fontenay-aux-Roses CEDEX, France.
authors.forename: Josée
authors.initials: J
authors.lastname: Guirouilh-Barbat
authors.forename: Sylvie
authors.initials: S
authors.lastname: Huck
authors.forename: Pascale
authors.initials: P
authors.lastname: Bertrand
authors.forename: Livia
authors.initials: L
authors.lastname: Pirzio
authors.forename: Chantal
authors.initials: C
authors.lastname: Desmaze
authors.forename: Laure
authors.initials: L
authors.lastname: Sabatier
authors.forename: Bernard S
authors.initials: BS
authors.lastname: Lopez
mesh_terms: D000818:Animals; D034961:Antigens, Nuclear / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence / Q000235:genetics; D016466:CHO Cells; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015321:Gene Rearrangement / Q000235:genetics*; D016678:Genome; D042822:Genomic Instability / Q000235:genetics*; D000072200:Ku Autoantigen; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics; D014178:Translocation, Genetic / Q000235:genetics
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; C000606510:Xrcc6 protein, mouse; D000072200:Ku Autoantigen