Disruption of the Arabidopsis AtKu80 gene demonstrates an essential role for AtKu80 protein in efficient repair of DNA double-strand breaks in vivo.
Double-strand breaks (DSBs) in DNA may occur spontaneously in the cell or be induced experimentally by gamma-irradiation, and represent one of the most serious threats to genomic integrity. Non-homologous end joining (NHEJ) rather than homologous recombination appears to be the major pathway for DSB repair in humans and plants, and it may also be the major route whereby T-DNA integrates into the plant genome during cell transformation. In yeast and mammals, the exposed ends of damaged DNA are bound with high affinity by a dimer of Ku70 and Ku80 proteins, which protects the ends from exonucleases and juxtaposes the two ends of the DSB, independent of sequence homology. Here we report the functional characterization of Ku70 and Ku80 from Arabidopsis thaliana, and demonstrate that AtKu80 and AtKu70 form a heterodimer with DNA binding activity that is specific for DNA ends. An atku80 knockout mutant shows hypersensitivity to the DNA-damaging agents menadione and bleomycin, consistent with a role for AtKu80 in the repair of DSBs in vivo in Arabidopsis.
School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
Christopher E
CE
West
Wanda M
WM
Waterworth
Geraint W
GW
Story
Paul A
PA
Sunderland
Qing
Q
Jiang
Clifford M
CM
Bray
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001761:Bleomycin / Q000494:pharmacology; D004249:DNA Damage; D004265:DNA Helicases / Q000235:genetics* / Q000502:physiology; D004260:DNA Repair / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D024483:Vitamin K 3 / Q000494:pharmacology
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D007093:Imidazoles; C463462:KU70 protein, Arabidopsis; C036483:T-DNA; D001761:Bleomycin; D012965:Sodium Chloride; D024483:Vitamin K 3; C029899:imidazole; D004265:DNA Helicases; C469228:Ku80 protein, Arabidopsis