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.

An R2R3-type transcription factor gene AtMYB59 regulates root growth and cell cycle progression in Arabidopsis

“…This phenomenon further suggests that the cell division process is altered in AtMYB59-transformed yeast cells, probably due to the inability to form a cell plate between the two daughter cells or due to other unknown mechanisms. It is also possible that the change in cell division in AtMYB59-transformed yeast cells is due to the interference of AtMYB59 with yeast CDC5, which shows similarity to the c-MYB protein and is involved in cell cycle progression [27].…”

The Arabidopsis Transcription Factor MYB12 Is a Flavonol-Specific Regulator of Phenylpropanoid Biosynthesis

“…MYB proteins have been identified in a large number of eukaryotic organisms ranging from fungi (Stober-Grässer et al, 1992;Ohi et al, 1994;TiceBaldwin et al, 1989) to plants (for review, see Martin and Paz-Ares, 1997;Jin and Martin, 1999) and to vertebrates (Gonda et al, 1985;Slamon et al, 1986;Nomura et al, 1988). While the MYB domain of c-MYB consists of three imperfect repeats (referred to as R1, R2, and R3), proteins with other numbers of MYB repeats have also been identified (Kranz et al, 2000;Riechmann et al, 2000;Stracke et al, 2001;Jiang et al, 2004).…”

CDC5, a DNA binding protein, positively regulates posttranscriptional processing and/or transcription of primary microRNA transcripts

“…It was first isolated from Schizosaccharomyces pombe as a cell cycle regulator. CDC5 is considered a putative transcription factor, as it is a MYB (a transcription factor)-related protein (26)(27)(28). In human and yeast, CDC5 has been shown to act as a component of spliceosome to participate in mRNA splicing (29,30).…”