Reference - PMID:8643672 - cdc18+ regulates initiation of DNA replication in Schizosaccharomyces pombe.

Reference summary

PubMed ID

PMID:8643672

Title

cdc18+ regulates initiation of DNA replication in Schizosaccharomyces pombe.

Authors

Muzi Falconi M, Brown GW, Kelly TJ

Citation

Proc Natl Acad Sci U S A 1996 Feb 20;93(4):1566-70

Publication year

1996

Abstract

In the fission yeast Schizosaccharomyces pombe the cdc18'+gene is required both for initiation of DNA replication and for coupling mitosis to the completion of S phase. Cells lacking Cdc18 fail to enter S phase but still undergo nuclear division. Expression of cdc18+ is sufficient to drive a G1-arrested cdc10ts mutant into the S phase of the cell cycle, indicating that cdc18+ represents a critical link between passage through START and the initiation of DNA replication. Here we show that Cdcl8 is a highly unstable protein that is expressed only once per cell cycle at the boundary between GI and S phase. De novo synthesis of Cdc18 is required before, but not after, the initiation of DNA replication, indicating that Cdc18 function is not necessary once the initiation event has occurred. Overproduction of the protein results in an accumulation of cells with DNA content of greater than 2C and delays mitosis, suggesting that Cdc18 is sufficient to cause reinitiation of DNA replication within a given cell cycle. Our data indicate that the synthesis of Cdc18 protein is a critical rate-limiting step in the initiation of DNA replication during each cell cycle. The extreme lability of the protein may contribute to the prevention of reinitiation.

Annotation