Protein-protein interactions of yeast DNA polymerase III with mammalian and yeast proliferating cell nuclear antigen (PCNA)/cyclin.
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.
Bauer
G A
GA
Department of Biological Chemistry, Washington University School of Medicine, St. Louis, MO 63110.
Burgers
P M
PM
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D004258:DNA Polymerase III / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D011067:Poly dA-dT / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013942:Thymine Nucleotides / Q000378:metabolism
D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D013942:Thymine Nucleotides; D011067:Poly dA-dT; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V; C024157:thymidine 5'-triphosphate