Positive and negative roles for cdc10 in cell cycle gene expression.
In this paper we describe properties of the cdc10-C4 mutant of the fission yeast Schizosaccharomyces pombe. The cdc10+ gene encodes a component of the DSC1Sp/MBF transcription complex, which is required for cell-cycle regulated expression at G1-S of several genes via cis-acting MCB (MIuI cell cycle box) elements. At permissive temperatures cdc10-C4 causes expression of MCB-regulated genes through the whole cell cycle, which in asynchronously dividing cells is manifested in overall higher expression levels. This overexpression phenotype is cold sensitive: in cdc10-C4 cells, MCB genes are expressed offprogressively higher levels at lower temperatures. In heterozygous cdc10-C4/cdc10+ diploid strains, MCB-regulated genes are not overexpressed, suggesting that loss, rather than alteration, of function of the cdc10-C4 gene product is the reason for unregulated target gene expression. Consistent with this, the cdc10-C4 mutant allele is known to encode a truncated protein. We have also overexpressed the region of the cdc10 protein absent in cdc10-C4 under the control of an inducible promoter. This induces a G1 delay, and additionally causes a reduction of the overexpression of MCB genes in cdc10-C4 strains. These results suggest that DSC1Sp/MBF represses, as well as activates, MCB gene expression during the cell cycle.
Institute of Cell and Molecular Biology, University of Edinburgh, UK.
C J
CJ
McInerny
P J
PJ
Kersey
J
J
Creanor
P A
PA
Fantes
D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase / Q000235:genetics; D016195:G2 Phase / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics* / Q000502:physiology; D005808:Genes, Recessive; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D005656:Fungal Proteins; D014157:Transcription Factors