Hsp90 levels affect telomere length in yeast.

Cdc13 is a Saccharomyces cerevisiae protein that binds to telomeric single-stranded DNA and regulates telomerase activity. Stnl has been shown by two-hybrid analysis to form a physical complex with Cdc13. Temperature-sensitive mutations in CDC13 and STN1, which are both essential genes, activate a DNA damage-dependent checkpoint which is the cause ...
of the arrest seen in the mutant strains. The stn1-13 mutation induces dramatic telomere elongation which is telomerase dependent, as shown here. Additional mutants for STN1, which show a tighter arrest phenotype than stn1-13, were generated in order to perform genetic screens aiming at uncovering new regulators of telomerase. HSC82, which encodes a conserved molecular chaperone of the Hsp90 family, was thus isolated as a high-dosage suppressor of a temperature-sensitive mutation in STN1. Overexpression of HSC82 also partially suppressed the growth defect of cdc13-1 cells. Overexpression of HSC82 was found to correct the telomeric defect associated with stn1 mutations. Shortening of telomeres was also observed in wild-type cells upon overexpression of HSC82, or of its temperature-inducible homologue, HSP82. These results identify Hsc82/Hsp82 as potential regulators of telomerase in yeast cells.
Mesh Terms:
Blotting, Northern, Cell Cycle Proteins, Cyclin B, DNA, Single-Stranded, Genes, cdc, HSP90 Heat-Shock Proteins, Heat-Shock Proteins, Hot Temperature, Mutation, Phenotype, Polymerase Chain Reaction, Protein Binding, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Telomerase, Telomere, Telomere-Binding Proteins, Two-Hybrid System Techniques
Mol. Genet. Genomics
Date: Mar. 01, 2001
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