title: Down-regulation of PARP-1, but not of Ku80 or DNA-PKcs', results in higher gene targeting efficiency.
abstract: The viability of non-homologous end-joining (NHEJ)-defective mice suggests that homologous recombination (HR) might take over its role in DNA repair. To test this hypothesis, we examined gene targeting frequencies (TF) in DNA-PK(cs), Ku80 and poly(ADP-ribose) polymerase (PARP-1) nullizygous cells. We observed a 3-fold TF increase in PARP-1 knockout embryonic stem (ES) cells, which is consistent with the predicted role of PARP-1 as a switch between HR and NHEJ. To a lesser extent, such effect could be reproduced upon chemical inhibition of PARP-1. However, TF was not enhanced in Ku80- or DNA-PK(cs)-defective cells. Our study also suggests an unexpected involvement of DNA-PK(cs) in HR.
authors.affiliation: Diabetes Research Institute, University of Miami, 1450 NW 10th Avenue, FL 33136, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Domínguez-Bendala
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Masutani
authors.forename: Jim
authors.initials: J
authors.lastname: McWhir
mesh_terms: D000818:Animals; D034961:Antigens, Nuclear / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D045643:DNA Repair Enzymes / Q000172:deficiency; D051747:DNA-Activated Protein Kinase / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D018390:Gene Targeting; D000072200:Ku Autoantigen; D051379:Mice; D018345:Mice, Knockout; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic / Q000235:genetics
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D051747:DNA-Activated Protein Kinase; C000606510:Xrcc6 protein, mouse; D000072200:Ku Autoantigen; D045643:DNA Repair Enzymes