Phosphorylation of the DNA polymerase alpha-primase B subunit is dependent on its association with the p180 polypeptide.
The B subunit of the DNA polymerase (pol) alpha-primase complex executes an essential role at the initial stage of DNA replication in Saccharomyces cerevisiae and is phosphorylated in a cell cycle-dependent manner. In this report, we show that the four subunits of the yeast DNA polymerase alpha-primase complex are assembled throughout the cell cycle, and physical association between newly synthesized pol alpha (p180) and unphosphorylated B subunit (p86) occurs very rapidly. Therefore, B subunit phosphorylation does not appear to modulate p180.p86 interaction. Conversely, by depletion experiments and by using a yeast mutant strain, which produces a low and constitutive level of the p180 polypeptide, we found that formation of the p180.p86 subcomplex is required for B subunit phosphorylation.
Ferrari
M
M
Dipartimento di Genetica e di Biologia dei Microrganismi, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
Lucchini
G
G
Plevani
P
P
Foiani
M
M
D002453:Cell Cycle; D004257:DNA Polymerase II / Q000378:metabolism*; D019915:DNA Primase; D004261:DNA Replication; D046911:Macromolecular Substances; D008970:Molecular Weight; D010766:Phosphorylation; D011485:Protein Binding; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology
D046911:Macromolecular Substances; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D004257:DNA Polymerase II