A 5' to 3' exonuclease functionally interacts with calf DNA polymerase epsilon

Proc Natl Acad Sci U S A. 1992 Oct 15;89(20):9377-81. doi: 10.1073/pnas.89.20.9377.


Analysis of fractions containing purified DNA polymerase epsilon from calf thymus has revealed the presence of a 5' to 3' exonuclease activity that is specific for a single strand of duplex DNA. This activity is capable of degrading a 3'-labeled oligonucleotide hybridized to M13mp18 DNA. When a second oligonucleotide primer is annealed 3 bases upstream, degradation of the downstream primer is strictly dependent on DNA synthesis from the upstream primer. Replacement of the downstream primer by an oligoribonucleotide of identical sequence results in a similar pattern of exonucleolytic activity. The activity has been highly purified and found to cosediment in glycerol gradients with a peptide of 56 kDa as judged by SDS/PAGE analysis. Effects of calf DNA polymerase alpha and delta on exonuclease activity are also observed but with differences in the pattern of products.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • DNA / metabolism
  • DNA Polymerase II / metabolism
  • DNA Polymerase III
  • DNA Replication*
  • DNA-Directed DNA Polymerase / metabolism*
  • Exonucleases / metabolism*
  • Macromolecular Substances
  • Molecular Sequence Data
  • Nucleic Acid Synthesis Inhibitors
  • Oligodeoxyribonucleotides / chemistry
  • Substrate Specificity
  • Thymus Gland / enzymology


  • Macromolecular Substances
  • Nucleic Acid Synthesis Inhibitors
  • Oligodeoxyribonucleotides
  • DNA
  • DNA Polymerase II
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • Exonucleases