title: Poly(ADP-ribose) polymerase 1 accelerates single-strand break repair in concert with poly(ADP-ribose) glycohydrolase.
abstract: Single-strand breaks are the commonest lesions arising in cells, and defects in their repair are implicated in neurodegenerative disease. One of the earliest events during single-strand break repair (SSBR) is the rapid synthesis of poly(ADP-ribose) (PAR) by poly(ADP-ribose) polymerase (PARP), followed by its rapid degradation by poly(ADP-ribose) glycohydrolase (PARG). While the synthesis of poly(ADP-ribose) is important for rapid rates of chromosomal SSBR, the relative importance of poly(ADP-ribose) polymerase 1 (PARP-1) and PARP-2 and of the subsequent degradation of PAR by PARG is unclear. Here we have quantified SSBR rates in human A549 cells depleted of PARP-1, PARP-2, and PARG, both separately and in combination. We report that whereas PARP-1 is critical for rapid global rates of SSBR in human A549 cells, depletion of PARP-2 has only a minor impact, even in the presence of depleted levels of PARP-1. Moreover, we identify PARG as a novel and critical component of SSBR that accelerates this process in concert with PARP-1.
authors.affiliation: Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom.
authors.forename: Anna E O
authors.initials: AE
authors.lastname: Fisher
authors.forename: Helfrid
authors.initials: H
authors.lastname: Hochegger
authors.forename: Shunichi
authors.initials: S
authors.lastname: Takeda
authors.forename: Keith W
authors.initials: KW
authors.lastname: Caldecott
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002645:Chickens; D053904:DNA Breaks, Single-Stranded; D004260:DNA Repair / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000172:deficiency / Q000378:metabolism*; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D000076105:X-ray Repair Cross Complementing Protein 1; D006861:Hydrogen Peroxide; D011065:Poly(ADP-ribose) Polymerases; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase