Aphidicolin-resistant and -sensitive base excision repair in wild-type and DNA polymerase beta-defective mouse cells

DNA Repair (Amst). 2004 Jul 2;3(7):703-10. doi: 10.1016/j.dnarep.2003.12.009.


Several DNA polymerases (Pols) can add complementary bases at the gap created during the base excision repair (BER). To characterize the BER resynthesis step, the repair of a single abasic site by wild-type and Pol beta-defective mouse cell extracts was analysed in the presence of aphidicolin, a specific inhibitor of replicative Pols. We show that there is a competition between distributive and processive Pols for the nucleotide addition at the primer terminus. In wild-type cell extracts, the initial nucleotide insertion involves mainly Pol beta but the elongation step is carried out by a replicative Pol. Conversely, in Pol beta-null cell extracts the synthesis step is carried out by a replicative Pol without any switching to an auxiliary polymerase. We present evidence that short-patch repair synthesis occurs even in the absence of both Pol beta and replicative Pols. Exogeneously added purified human Pol lambda was unable to stimulate this back-up synthesis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aphidicolin / pharmacology*
  • Base Sequence
  • Cell Extracts
  • DNA Polymerase beta / deficiency
  • DNA Polymerase beta / genetics
  • DNA Polymerase beta / metabolism*
  • DNA Repair / drug effects*
  • Enzyme Inhibitors / pharmacology*
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Kinetics
  • Mice
  • Mice, Knockout
  • Molecular Sequence Data
  • Oligonucleotides / genetics
  • Oligonucleotides / metabolism
  • Proliferating Cell Nuclear Antigen / metabolism


  • Cell Extracts
  • Enzyme Inhibitors
  • Oligonucleotides
  • Proliferating Cell Nuclear Antigen
  • Aphidicolin
  • DNA Polymerase beta