Analysis of fractions containing purified DNA polymerase ε 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 α and δ on exonuclease activity are also observed but with differences in the pattern of products.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Oct 28 1992|
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