Physical and functional interactions of the tumor suppressor protein p53 and DNA polymerase alpha-primase

Nucleic Acids Res. 2002 Apr 1;30(7):1493-9. doi: 10.1093/nar/30.7.1493.


The wild-type form of p53 contains an intrinsic 3'-5'-exonuclease activity. As p53 forms a complex with DNA polymerase alpha-primase (pol-prim) in vivo this finding suggests that p53 might cooperate with pol-prim to stabilize the genetic information of living cells. To test this hypothesis, exonuclease-free DNA pol-prim was expressed alone or together with p53 for purification. Pol-prim formed a complex with p53, which was purified by ion exchange and immunoaffinity chromatography from baculovirus-infected insect cells. The p53-containing pol-prim fractions removed a 3'-unpaired nucleotide with a 1.5-2-fold higher rate than a paired nucleotide, whereas the four subunit pol-prim did not have any exonuclase activity. Therefore, only p53/pol-prim was able to elongate a primer-template that contained a 3'-unpaired primer end in vitro. To achieve this, the 3'-5'-exonuclease activity of p53 excised the unpaired nucleotide at the 3'-end of the primer and created a paired 3'-end, which pol-prim was able to elongate. The exonuclease activity of p53 as well as the elongation of a primer with a mispaired 3'-end was inhibited specifically by the anti-p53 monoclonal antibodies PAb240 and PAb421.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Baculoviridae / genetics
  • Base Pair Mismatch / genetics
  • Cell Line
  • DNA / genetics
  • DNA / metabolism
  • DNA Polymerase I / genetics
  • DNA Polymerase I / metabolism*
  • DNA Primase / genetics
  • DNA Primase / metabolism*
  • Exonucleases / metabolism
  • Genetic Vectors / genetics
  • Humans
  • Macromolecular Substances
  • Precipitin Tests
  • Protein Binding
  • Transfection
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*


  • Macromolecular Substances
  • Tumor Suppressor Protein p53
  • DNA
  • DNA Primase
  • DNA polymerase alpha-primase
  • DNA Polymerase I
  • Exonucleases