The Schizosaccharomyces pombe cdc5+ gene encodes an essential protein with homology to c-Myb

EMBO J. 1994 Jan 15;13(2):471-83.


The Schizosaccharomyces pombe cdc5+ gene was identified in the first screen for cell division cycle mutants in this yeast. The cdc5+ gene was reported to be required for nuclear division but because of its modest elongation and leaky nature at the non-permissive temperature, it was not investigated further. Here, we report the characterization of the single allele of this gene, cdc5-120, in more detail. The mutant arrests with a 2N DNA content and a single interphase nucleus. Further genetic analyses suggest that cdc5+ gene function is essential in the G2 phase of the cell cycle. We have cloned and sequenced the cdc5+ gene. The deduced protein sequence predicts that Cdc5 is an 87 kDa protein and contains a region sharing significant homology with the DNA binding domain of the Myb family of transcription factors. Deletion mapping of the cdc5+ gene has shown that the N-terminal 232 amino acids of the protein, which contain the Myb-related region, are sufficient to complement the cdc5ts strain. A cdc5 null mutant was generated by homologous recombination. Haploid cells lacking cdc5+ are inviable, indicating that cdc5+ is an essential gene. A fusion protein consisting of bacterial glutathione S-transferase joined in-frame to the N-terminal 127 amino acids of the Cdc5 protein is able to bind to DNA cellulose at low salt concentrations. This evidence suggests that cdc5+ might encode a transcription factor whose activity is required for cell cycle progression and growth during G2.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Cycle Proteins*
  • Cloning, Molecular
  • DNA Replication
  • DNA, Fungal / metabolism
  • DNA-Binding Proteins / genetics*
  • Fungal Proteins / genetics*
  • Genes, Fungal
  • Genetic Complementation Test
  • Hydroxyurea / metabolism
  • Molecular Sequence Data
  • Phenotype
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins c-myb
  • Restriction Mapping
  • Schizosaccharomyces / genetics*
  • Schizosaccharomyces / growth & development
  • Schizosaccharomyces pombe Proteins
  • Sequence Homology, Amino Acid


  • Cell Cycle Proteins
  • DNA, Fungal
  • DNA-Binding Proteins
  • Fungal Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-myb
  • Schizosaccharomyces pombe Proteins
  • cdc5 protein, S pombe
  • Hydroxyurea

Associated data

  • GENBANK/L19525