title: The yeast analog of mammalian cyclin/proliferating-cell nuclear antigen interacts with mammalian DNA polymerase delta.
abstract: DNA polymerase III from Saccharomyces cerevisiae is analogous to the mammalian DNA polymerase delta by several criteria, including an increased synthetic activity on poly(dA).oligo(dT) (40:1 nucleotide ratio) in the presence of calf thymus proliferating-cell nuclear antigen (PCNA), or cyclin. This stimulation assay has been used to purify the yeast analog of PCNA/cyclin (yPCNA) to homogeneity. yPCNA is a trimer or tetramer (Mr approximately 82,000) of identical subunits with a denatured Mr of 26,000. On a molar basis yPCNA and calf thymus PCNA/cyclin are equally active in stimulating DNA synthesis by DNA polymerase III. About 10 times more yPCNA than calf thymus PCNA/cyclin is needed, however, to stimulate calf thymus DNA polymerase delta, and the degree of stimulation obtained at saturating levels of yPCNA is a factor of 2-3 less than with calf thymus PCNA/cyclin. Both stimulatory proteins exert their effect in an identical fashion, i.e., by increasing the processivity of the DNA polymerase. Yeast DNA polymerases I and II and calf thymus DNA polymerase alpha are not stimulated by yPCNA. Treatment of logarithmic-phase cells with hydroxyurea blocks them in the S phase and produces a 4- to 5-fold increase in yPCNA.
mesh_terms: D000818:Animals; D000946:Antigens, Fungal / Q000302:isolation & purification; D002417:Cattle; D002453:Cell Cycle; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen; D012441:Saccharomyces cerevisiae / Q000032:analysis* / Q000166:cytology / Q000201:enzymology / Q000276:immunology
chemical_list: D000946:Antigens, Fungal; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase