title: PARP-3 and APLF function together to accelerate nonhomologous end-joining.
abstract: PARP-3 is a member of the ADP-ribosyl transferase superfamily of unknown function. We show that PARP-3 is stimulated by DNA double-strand breaks (DSBs) in vitro and functions in the same pathway as the poly (ADP-ribose)-binding protein APLF to accelerate chromosomal DNA DSB repair. We implicate PARP-3 in the accumulation of APLF at DSBs and demonstrate that APLF promotes the retention of XRCC4/DNA ligase IV complex in chromatin, suggesting that PARP-3 and APLF accelerate DNA ligation during nonhomologous end-joining (NHEJ). Consistent with this, we show that class switch recombination in Aplf(-/-) B cells is biased toward microhomology-mediated end-joining, a pathway that operates in the absence of XRCC4/DNA ligase IV, and that the requirement for PARP-3 and APLF for NHEJ is circumvented by overexpression of XRCC4/DNA ligase IV. These data identify molecular roles for PARP-3 and APLF in chromosomal DNA double-strand break repair reactions.
authors.affiliation: Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Rulten
authors.forename: Anna E O
authors.initials: AE
authors.lastname: Fisher
authors.forename: Isabelle
authors.initials: I
authors.lastname: Robert
authors.forename: Maria C
authors.initials: MC
authors.lastname: Zuma
authors.forename: Michele
authors.initials: M
authors.lastname: Rouleau
authors.forename: Limei
authors.initials: L
authors.lastname: Ju
authors.forename: Guy
authors.initials: G
authors.lastname: Poirier
authors.forename: Bernardo
authors.initials: B
authors.lastname: Reina-San-Martin
authors.forename: Keith W
authors.initials: KW
authors.lastname: Caldecott
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000502:physiology; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D017353:Gene Deletion; D006801:Humans; D051379:Mice; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000075223:Poly-ADP-Ribose Binding Proteins; D011993:Recombinant Fusion Proteins / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D010750:Phosphoproteins; D000075223:Poly-ADP-Ribose Binding Proteins; D011993:Recombinant Fusion Proteins; C480979:PARP3 protein, human; D011065:Poly(ADP-ribose) Polymerases; C459820:Parp2 protein, mouse; C520557:APLF protein, human; C555924:APLF protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase