title: Poly(ADP-ribose) reactivates stalled DNA topoisomerase I and Induces DNA strand break resealing.
abstract: Regulating the topological state of DNA is a vital function of the enzyme DNA topoisomerase I. However, when acting on damaged DNA, topoisomerase I may get trapped in a covalent complex with nicked DNA (stalled topoisomerase I), that, if unrepaired, may lead to genomic instability or cell death. Here we show that ADP-ribose polymers target specific domains of topoisomerase I and reprogram the enzyme to remove itself from cleaved DNA and close the resulting gap. Two members of the poly(ADP-ribose) polymerase family, PARP-1 and 2, act as poly(ADP-ribose) carriers to stalled topoisomerase I sites and induce efficient repair of enzyme-associated DNA strand breaks. Thus, by counteracting topoisomerase I-induced DNA damage, PARP-1 and PARP-2 act as positive regulators of genomic stability in eukaryotic cells.
authors.affiliation: Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: Malanga
authors.forename: Felix R
authors.initials: FR
authors.lastname: Althaus
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004249:DNA Damage; D004260:DNA Repair; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
chemical_list: D011064:Poly Adenosine Diphosphate Ribose; C483041:PARP2 protein, human; D011065:Poly(ADP-ribose) Polymerases; D004264:DNA Topoisomerases, Type I