title: A 48-kDa, S-antigen-like phosphoprotein in yeast DNA-replicative complex preparations.
abstract: A 48-kDa protein from the budding yeast Saccharomyces cerevisiae is antigenically and structurally similar to S-antigen from retina. Eight anti-S-antigen monoclonal antibodies, directed against distinct epitopes, cross-reacted with a yeast 48-kDa protein. Structural similarity between the bovine and yeast proteins was further demonstrated by comparison of tryptic peptide fragments containing one of these epitopes. This 48-kDa yeast protein appears to be a component of the replicative complex of the cell. It was found associated with immunoaffinity-purified yeast DNA polymerase I-primase and with yeast DNA-replicative complex. The 48-kDa protein was phosphorylated by a protein kinase activity endogenous to the replicative complex preparation. This phosphorylation was dependent on the cell division cycle gene CDC7. In addition, authentic bovine S-antigen, when added to yeast DNA polymerase I-primase, stimulated polymerase activity. These findings suggest that the yeast S-antigen-like protein may play a role in replication, and they raise the possibility that it may be involved in traversal of the G1/S boundary of the cell cycle.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, New Orleans 70112.
authors.forename: N E
authors.initials: NE
authors.lastname: Jeansonne
authors.forename: S M
authors.initials: SM
authors.lastname: Jazwinski
authors.forename: L A
authors.initials: LA
authors.lastname: Donoso
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000941:Antigens / Q000276:immunology*; D019393:Arrestin; D015153:Blotting, Western; D002417:Cattle; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins / Q000276:immunology*; D005656:Fungal Proteins / Q000032:analysis* / Q000276:immunology; D008565:Membrane Proteins / Q000032:analysis / Q000276:immunology; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000032:analysis* / Q000276:immunology; D010766:Phosphorylation; D011233:Precipitin Tests; D012441:Saccharomyces cerevisiae / Q000032:analysis*; D014357:Trypsin
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D019393:Arrestin; D005136:Eye Proteins; D005656:Fungal Proteins; D008565:Membrane Proteins; D010750:Phosphoproteins; D004259:DNA-Directed DNA Polymerase; D014357:Trypsin