title: DNA 3'-phosphatase activity is critical for rapid global rates of single-strand break repair following oxidative stress.
abstract: Oxidative stress is a major source of chromosome single-strand breaks (SSBs), and the repair of these lesions is retarded in neurodegenerative disease. The rate of the repair of oxidative SSBs is accelerated by XRCC1, a scaffold protein that is essential for embryonic viability and that interacts with multiple DNA repair proteins. However, the relative importance of the interactions mediated by XRCC1 during oxidative stress in vivo is unknown. We show that mutations that disrupt the XRCC1 interaction with DNA polymerase beta or DNA ligase III fail to slow SSB repair in proliferating CHO cells following oxidative stress. In contrast, mutation of the domain that interacts with polynucleotide kinase/phosphatase (PNK) and Aprataxin retards repair, and truncated XRCC1 encoding this domain fully supports this process. Importantly, the impact of mutating the protein domain in XRCC1 that binds these end-processing factors is circumvented by the overexpression of wild-type PNK but not by the overexpression of PNK harboring a mutated DNA 3'-phosphatase domain. These data suggest that DNA 3'-phosphatase activity is critical for rapid rates of chromosomal SSB repair following oxidative stress, and that the XRCC1-PNK interaction ensures that this activity is not rate limiting in vivo.
authors: Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom.
authors: Claire
authors: C
authors: Breslin
authors: Keith W
authors: KW
authors: Caldecott
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D053904:DNA Breaks, Single-Stranded; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009708:Nucleotidases / Q000235:genetics / Q000378:metabolism*; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D000075223:Poly-ADP-Ribose Binding Proteins; D011116:Polynucleotide 5'-Hydroxyl-Kinase / Q000235:genetics / Q000378:metabolism; D000076105:X-ray Repair Cross Complementing Protein 1; D029867:Xenopus Proteins
chemical_list: C438188:APTX protein, human; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016877:Oxidants; D010940:Plant Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D029867:Xenopus Proteins; D006861:Hydrogen Peroxide; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D019951:DNA Polymerase beta; D009708:Nucleotidases; C039170:deoxynucleotide 3'-phosphatase; D011088:DNA Ligases; D000072481:DNA Ligase ATP; C000618816:DNA ligase III alpha protein, Xenopus; C000618817:LIG3 protein, human