Protein-protein interactions of yeast DNA polymerase III with mammalian and yeast proliferating cell nuclear antigen (PCNA)/cyclin

Biochim Biophys Acta. 1988 Dec 20;951(2-3):274-9. doi: 10.1016/0167-4781(88)90097-8.


We have previously reported the purification of yeast analogs to mammalian DNA polymerase delta and proliferating-cell nuclear antigen (PCNA)/cyclin: DNA polymerase III and yeast PCNA, respectively. Through the use of gel-filtration chromatography, we have studied the interaction of the model template-primer system poly(dA).(dT)16 (40:1) with yeast DNA polymerase III and with PCNAs. Yeast DNA polymerase III binds to the DNA in the absence of yeast PCNA/cyclin, but comigration of either yeast or calf thymus PCNA/cyclin with the DNA requires the additional presence of yeast DNA polymerase III. We could also isolate a DNA-calf thymus DNA polymerase delta-calf thymus PCNA/cyclin complex. From these data, we propose that PCNA/cyclin is involved not in the binding step of the polymerase to the template-primer, but in the elongation step. The 3'----5' exonuclease associated with yeast DNA polymerase III acts in a distributive manner on poly(dA).(pT)16, and dissociates from the DNA when addition of dTTP allows switching from the exonuclease to the polymerase mode. Addition of PCNA/cyclin had no effect on these activities.

Publication types

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

MeSH terms

  • Animals
  • Cattle
  • Chromatography, Gel
  • DNA Polymerase III / metabolism*
  • DNA-Directed DNA Polymerase / metabolism*
  • Exodeoxyribonuclease V
  • Exodeoxyribonucleases / metabolism
  • Nuclear Proteins / metabolism*
  • Poly dA-dT / metabolism
  • Proliferating Cell Nuclear Antigen
  • Saccharomyces cerevisiae / enzymology*
  • Thymine Nucleotides / metabolism


  • Nuclear Proteins
  • Proliferating Cell Nuclear Antigen
  • Thymine Nucleotides
  • Poly dA-dT
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • Exodeoxyribonucleases
  • Exodeoxyribonuclease V
  • thymidine 5'-triphosphate