Functionally homologous DNA replication genes in fission and budding yeast

J Cell Sci. 1999 Jul:112 ( Pt 14):2381-90. doi: 10.1242/jcs.112.14.2381.

Abstract

The cdc18(+) gene of the fission yeast Schizosaccharomyces pombe is involved in the initiation of DNA replication as well as in coupling the S phase to mitosis. In this work, we show that the Saccharomyces cerevisiae CDC6 gene complements cdc18-K46 ts and cdc18 deletion mutant S. pombe strains. The budding yeast gene suppresses both the initiation and the checkpoint defects associated with the lack of cdc18(+). The Cdc6 protein interacts in vivo with Cdc2 kinase complexes. Interestingly, Cdc6 is an in vitro substrate for Cdc13/Cdc2 and Cig1/Cdc2, but not for Cig2/Cdc2-associated kinases. Overexpression of Cdc6 in fission yeast induces multiple rounds of S-phase in the absence of mitosis and cell division. This CDC6-dependent continuous DNA synthesis phenotype is independent of the presence of a functional cdc18(+) gene product and, significantly, requires only Cig2/Cdc2-associated kinase activity. Finally, these S. pombe over-replicating cells do not require any protein synthesis other than that of Cdc6. Our data strongly suggest that CDC6 and cdc18(+) are functional homologues and also support the idea that controls restricting genome duplication diverge in fission and budding yeast.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • CDC2 Protein Kinase / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cyclin B / metabolism
  • Cyclins / metabolism
  • Cycloheximide / pharmacology
  • DNA Primers / genetics
  • DNA Replication / genetics*
  • DNA, Fungal / biosynthesis
  • DNA, Fungal / genetics
  • Fungal Proteins / metabolism
  • Genes, Fungal*
  • Genetic Complementation Test
  • Mutation
  • Protein Synthesis Inhibitors / pharmacology
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Schizosaccharomyces / drug effects
  • Schizosaccharomyces / genetics*
  • Schizosaccharomyces / metabolism
  • Schizosaccharomyces pombe Proteins*
  • Species Specificity

Substances

  • CDC6 protein, S cerevisiae
  • Cell Cycle Proteins
  • Cig2 protein, S pombe
  • Cyclin B
  • Cyclins
  • DNA Primers
  • DNA, Fungal
  • Fungal Proteins
  • Protein Synthesis Inhibitors
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces pombe Proteins
  • cdc18 protein, S pombe
  • Cycloheximide
  • CDC2 Protein Kinase