XRCC1 polypeptide interacts with DNA polymerase beta and possibly poly (ADP-ribose) polymerase, and DNA ligase III is a novel molecular 'nick-sensor' in vitro

Nucleic Acids Res. 1996 Nov 15;24(22):4387-94. doi: 10.1093/nar/24.22.4387.


The DNA repair proteins XRCC1 and DNA ligase III are physically associated in human cells and directly interact in vitro and in vivo. Here, we demonstrate that XRCC1 is additionally associated with DNA polymerase-beta in human cells and that these polypeptides also directly interact. We also present data suggesting that poly (ADP-ribose) polymerase can interact with XRCC1. Finally, we demonstrate that DNA ligase III shares with poly (ADP-ribose) polymerase the novel function of a molecular DNA nick-sensor, and that the DNA ligase can inhibit activity of the latter polypeptide in vitro. Taken together, these data suggest that the activity of the four polypeptides described above may be co-ordinated in human cells within a single multiprotein complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA Ligase ATP
  • DNA Ligases / chemistry
  • DNA Ligases / genetics
  • DNA Ligases / metabolism*
  • DNA Polymerase I / chemistry
  • DNA Polymerase I / genetics
  • DNA Polymerase I / metabolism*
  • DNA Repair*
  • DNA-Binding Proteins / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Molecular Sequence Data
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Poly-ADP-Ribose Binding Proteins
  • X-ray Repair Cross Complementing Protein 1
  • Xenopus Proteins
  • Zinc Fingers


  • DNA-Binding Proteins
  • Poly-ADP-Ribose Binding Proteins
  • X-ray Repair Cross Complementing Protein 1
  • XRCC1 protein, human
  • Xenopus Proteins
  • Poly(ADP-ribose) Polymerases
  • DNA Polymerase I
  • DNA Ligases
  • DNA Ligase ATP
  • DNA ligase III alpha protein, Xenopus
  • LIG3 protein, human