DNA polymerase beta -mediated long patch base excision repair. Poly(ADP-ribose)polymerase-1 stimulates strand displacement DNA synthesis

J Biol Chem. 2001 Aug 31;276(35):32411-4. doi: 10.1074/jbc.C100292200. Epub 2001 Jul 5.


Recently, photoaffinity labeling experiments with mouse cell extracts suggested that PARP-1 functions as a surveillance protein for a stalled BER intermediate. To further understand the role of PARP-1 in BER, we examined the DNA synthesis and flap excision steps in long patch BER using a reconstituted system containing a 34-base pair BER substrate and five purified human enzymes: uracil-DNA glycosylase, apurinic/apyrimidinic endonuclease, DNA polymerase beta, flap endonuclease-1 (FEN-1), and PARP-1. PARP-1 stimulates strand displacement DNA synthesis by DNA polymerase beta in this system; this stimulation is dependent on the presence of FEN-1. PARP-1 and FEN-1, therefore, cooperate to activate long patch BER. The results are discussed in the context of a model for BER sub-pathway choice, illustrating a dual role for PARP-1 as a surveillance protein for a stalled BER intermediate and an activating factor for long patch BER DNA synthesis.

MeSH terms

  • Amino Acid Substitution
  • Base Sequence
  • Circular Dichroism
  • DNA / biosynthesis
  • DNA / chemistry
  • DNA / metabolism*
  • DNA Glycosylases*
  • DNA Polymerase beta / chemistry
  • DNA Polymerase beta / metabolism*
  • DNA Repair*
  • DNA Replication
  • Endodeoxyribonucleases / metabolism
  • Flap Endonucleases
  • Humans
  • Mutagenesis, Site-Directed
  • N-Glycosyl Hydrolases / metabolism
  • Oligodeoxyribonucleotides / chemistry
  • Oligodeoxyribonucleotides / metabolism
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Protein Conformation
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Uracil-DNA Glycosidase


  • Oligodeoxyribonucleotides
  • Recombinant Proteins
  • DNA
  • Poly(ADP-ribose) Polymerases
  • DNA Polymerase beta
  • Endodeoxyribonucleases
  • Flap Endonucleases
  • FEN1 protein, human
  • DNA Glycosylases
  • N-Glycosyl Hydrolases
  • Uracil-DNA Glycosidase