title: PARP-3 associates with polycomb group bodies and with components of the DNA damage repair machinery.
abstract: Poly(ADP-ribose) polymerase 3 (PARP-3) is a novel member of the PARP family of enzymes that synthesize poly(ADP-ribose) on themselves and other acceptor proteins. Very little is known about this PARP, which is closely related to PARP-1 and PARP-2. By sequence analysis, we find that PARP-3 may be expressed in two isoforms which we studied in more detail to gain insight into their possible functions. We find that both PARP-3 isoforms, transiently expressed as GFP or FLAG fusions, are nuclear. Detection of endogenous PARP-3 with a specific antibody also shows a widespread nuclear distribution, appearing in numerous small foci and a small number of larger foci. Through co-localization experiments and immunoprecipitations, the larger nuclear foci were identified as Polycomb group bodies (PcG bodies) and we found that PARP-3 is part of Polycomb group protein complexes. Furthermore, using a proteomics approach, we determined that both PARP-3 isoforms are part of complexes comprising DNA-PKcs, PARP-1, DNA ligase III, DNA ligase IV, Ku70, and Ku80. Our findings suggest that PARP-3 is a nuclear protein involved in transcriptional silencing and in the cellular response to DNA damage.
authors.affiliation: Health and Environment Unit, Laval University Medical Research Centre, CHUQ, Faculty of Medicine, Laval University, 2705 Blvd Laurier, Sainte-Foy, Québec, G1V 4G2, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Rouleau
authors.forename: D
authors.initials: D
authors.lastname: McDonald
authors.forename: P
authors.initials: P
authors.lastname: Gagné
authors.forename: M-E
authors.initials: ME
authors.lastname: Ouellet
authors.forename: A
authors.initials: A
authors.lastname: Droit
authors.forename: J M
authors.initials: JM
authors.lastname: Hunter
authors.forename: S
authors.initials: S
authors.lastname: Dutertre
authors.forename: C
authors.initials: C
authors.lastname: Prigent
authors.forename: M J
authors.initials: MJ
authors.lastname: Hendzel
authors.forename: G G
authors.initials: GG
authors.lastname: Poirier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D034961:Antigens, Nuclear / Q000378:metabolism; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002522:Chlorocebus aethiops; D004247:DNA / Q000235:genetics*; D004249:DNA Damage / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D000072200:Ku Autoantigen; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D063146:Polycomb-Group Proteins; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D007527:Isoenzymes; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; D004247:DNA; C480979:PARP3 protein, human; D011065:Poly(ADP-ribose) Polymerases; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen