Cell cycle-dependent phosphorylation and dephosphorylation of the yeast DNA polymerase alpha-primase B subunit.
The yeast DNA polymerase alpha-primase B subunit functions in initiation of DNA replication. This protein is present in two forms, of 86 and 91 kDa, and the p91 polypeptide results from cell cycle-regulated phosphorylation of p86. The B subunit present in G1 arises by dephosphorylation of p91 while cells are exiting from mitosis, becomes phosphorylated in early S phase, and is competent and sufficient to initiate DNA replication. The B subunit transiently synthesized as a consequence of periodic transcription of the POL12 gene is phosphorylated no earlier than G2. Phosphorylation of the B subunit does not require execution of the CDC7-dependent step and ongoing DNA synthesis. We suggest that posttranslational modifications of the B subunit might modulate the role of DNA polymerase alpha-primase in DNA replication.
Foiani
M
M
Dipartimento di Genetica e di Biologia dei Microrganismi, Università degli Studi di Milano, Italy.
Liberi
G
G
Lucchini
G
G
Plevani
P
P
D000135:Acid Phosphatase; D015153:Blotting, Western; D002453:Cell Cycle / Q000502:physiology*; D019915:DNA Primase; D004261:DNA Replication; D016193:G1 Phase; D015870:Gene Expression; D005838:Genotype; D007700:Kinetics; D046911:Macromolecular Substances; D016296:Mutagenesis; D010766:Phosphorylation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics; D011198:Solanum tuberosum / Q000201:enzymology; D013997:Time Factors
D046911:Macromolecular Substances; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D000135:Acid Phosphatase