A yeast heat shock transcription factor (Hsf1) mutant is defective in both Hsc82/Hsp82 synthesis and spindle pole body duplication.
Cdc28 is a cyclin-dependent protein kinase of Saccharomyces cerevisiae that is required for the G1/S and G2/M transitions of the cell division cycle. All previously described cdc28 mutants aside from cdc28-1N arrest division specifically in the G1 phase. cdc28-1N arrests division in G2/mitosis. We show here that the cdc28-109 mutant ... exhibits a mixed cell division arrest at 37 degrees C with cells in both the G1 and G2 phases. In order to identify proteins that functionally interact with Cdc28, we isolated mutants that are colethal with cdc28-109 at its permissive temperature. We describe here our phenotypic analysis of two such mutants, hsf1-82 and ydj1-10, that affect the heat shock transcription factor and a yeast dnaj-like protein chaperone, respectively. hsf1-82 and ydj1-10 temperature-sensitive mutants arrest the cell division cycle at several stages. However, one predominant class of cells in both mutants was arrested with a large bud and a single vertex of microtubules. Electron microscopic analysis of such hsf1-82 cells showed that they contained an unduplicated spindle pole body with an enlarged half-bridge. Two-dimensional gel electrophoresis of total cell proteins revealed that the hsf1-82 cells were specifically defective in the expression of the Hsc82 and Hsp82 proteins. Furthermore, the hsf1-82 mutation was suppressed by the HSC82 gene on a multicopy plasmid that restored Hsc82 protein to high levels in these cells. These results show that Hsf1 is required for spindle pole body duplication at 37 degrees C.
Mesh Terms:
Alleles, CDC28 Protein Kinase, S cerevisiae, Cell Cycle, DNA-Binding Proteins, Fungal Proteins, Genotype, HSP90 Heat-Shock Proteins, Heat-Shock Proteins, Microscopy, Electron, Mitotic Spindle Apparatus, Models, Structural, Mutation, Polymerase Chain Reaction, Protein Kinases, Protein Structure, Tertiary, Saccharomyces, Saccharomyces cerevisiae Proteins, Static Electricity, Transcription Factors, Tubulin
Alleles, CDC28 Protein Kinase, S cerevisiae, Cell Cycle, DNA-Binding Proteins, Fungal Proteins, Genotype, HSP90 Heat-Shock Proteins, Heat-Shock Proteins, Microscopy, Electron, Mitotic Spindle Apparatus, Models, Structural, Mutation, Polymerase Chain Reaction, Protein Kinases, Protein Structure, Tertiary, Saccharomyces, Saccharomyces cerevisiae Proteins, Static Electricity, Transcription Factors, Tubulin
J. Cell. Sci.
Date: Aug. 01, 1997
PubMed ID: 9296388
View in: Pubmed Google Scholar
Download Curated Data For This Publication
14631
Switch View:
- Interactions 5