title: A cellular defense pathway regulating transcription through poly(ADP-ribosyl)ation in response to DNA damage.
abstract: DNA damage is known to trigger key cellular defense pathways such as those involved in DNA repair. Here we provide evidence for a previously unrecognized pathway regulating transcription in response to DNA damage and show that this regulation is mediated by the abundant nuclear enzyme poly(ADP-ribose) polymerase. We found that poly(ADP-ribose) polymerase reduced the rate of transcription elongation by RNA polymerase II, suggesting that poly(ADP-ribose) polymerase negatively regulates transcription, possibly through the formation of poly(ADP-ribose) polymerase-RNA complexes. In damaged cells, poly(ADP-ribose) polymerase binds to DNA breaks and automodifies itself in the presence of NAD(+), resulting in poly(ADP-ribose) polymerase inactivation. We found that automodification of poly(ADP-ribose) polymerase in response to DNA damage resulted in the up-regulation of transcription, presumably because automodified poly(ADP-ribose) polymerase molecules were released from transcripts, thereby relieving the block on transcription. Because agents that damage DNA damage RNA as well, up-regulation of RNA synthesis in response to DNA damage may provide cells with a mechanism to compensate for the loss of damaged transcripts and may be critical for cell survival after exposure to DNA-damaging agents.
authors.affiliation: DNA Repair Group, Health and Environment Unit, Laval University Medical Research Center, Centre Hospitalier Universitaire de Québec (CHUQ), Faculty of Medicine, Laval University, 2705 Boulevard Laurier, Ste-Foy, QC G1V 4G2, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Vispe
authors.forename: T M
authors.initials: TM
authors.lastname: Yung
authors.forename: J
authors.initials: J
authors.lastname: Ritchot
authors.forename: H
authors.initials: H
authors.lastname: Serizawa
authors.forename: M S
authors.initials: MS
authors.lastname: Satoh
mesh_terms: D002460:Cell Line; D002474:Cell-Free System; D003001:Cloning, Molecular; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D004249:DNA Damage; D004260:DNA Repair; D004926:Escherichia coli; D005786:Gene Expression Regulation; D006801:Humans; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: C505032:CFTR protein, human; D011994:Recombinant Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011064:Poly Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases; D012319:RNA Polymerase II