title: The Schizosaccharomyces pombe cdc5+ gene encodes an essential protein with homology to c-Myb.
abstract: 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.
authors.affiliation: Department of Cell Biology, School of Medicine, Vanderbilt University, Nashville, TN 37232.
authors.forename: R
authors.initials: R
authors.lastname: Ohi
authors.forename: D
authors.initials: D
authors.lastname: McCollum
authors.forename: B
authors.initials: B
authors.lastname: Hirani
authors.forename: G J
authors.initials: GJ
authors.lastname: Den Haese
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: J D
authors.initials: JD
authors.lastname: Burke
authors.forename: K
authors.initials: K
authors.lastname: Turner
authors.forename: K L
authors.initials: KL
authors.lastname: Gould
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D004261:DNA Replication; D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D006918:Hydroxyurea / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D020598:Proto-Oncogene Proteins c-myb; D015183:Restriction Mapping; D012568:Schizosaccharomyces / Q000235:genetics* / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D029702:Schizosaccharomyces pombe Proteins; C085875:cdc5 protein, S pombe; D006918:Hydroxyurea