Saccharomyces cerevisiae cdc2 mutants arrest in the S-phase of the cell cycle when grown at the non-permissive temperature, implicating this gene product as essential for DNA synthesis. The CDC2 gene has been cloned from a yeast genomic library in vector YEp13 by complementation of a cdc2 mutation. An open reading frame coding for a 1093 amino acid long protein with a calculated mol. wt of 124 518 was determined from the sequence. This putative protein shows significant homology with a class of eukaryotic DNA polymerases exemplified by human DNA polymerase α and herpes simplex virus DNA polymerase. Fractionation of extracts from cdc2 strains showed that these mutants lacked both the polymerase and proofreading 3'-5' exonuclease activity of DNA polymerase III, the yeast analog of mammalian DNA polymerase δ. These studies indicate that DNA polymerase III is an essential component of the DNA replication machinery.
|Number of pages||6|
|State||Published - 1989|