1 research outputs found
Genome-Wide Analysis of the Effects of Heat Shock on a Saccharomyces cerevisiae Mutant With a Constitutively Activated cAMP-Dependent Pathway
We have used DNA microarray technology and 2-D gel electrophoresis combined with
mass spectrometry to investigate the effects of a drastic heat shock from 30ā to 50ā
on a genome-wide scale. This experimental condition is used to differentiate between
wild-type cells and those with a constitutively active cAMP-dependent pathway in
Saccharomyces cerevisiae. Whilst more than 50% of the former survive this shock,
almost all of the latter lose viability. We compared the transcriptomes of the wildtype
and a mutant strain deleted for the gene PDE2, encoding the high-affinity cAMP
phosphodiesterase before and after heat shock treatment. We also compared the two
heat-shocked samples with one another, allowing us to determine the changes that
occur in the pde2Ī mutant which cause such a dramatic loss of viability after heat
shock. Several genes involved in ergosterol biosynthesis and carbon source utilization
had altered expression levels, suggesting that these processes might be potential
factors in heat shock survival. These predictions and also the effect of the different
phases of the cell cycle were confirmed by biochemical and phenotypic analyses. 146
genes of previously unknown function were identified amongst the genes with altered
expression levels and deletion mutants in 13 of these genes were found to be highly
sensitive to heat shock. Differences in response to heat shock were also observed at
the level of the proteome, with a higher level of protein degradation in the mutant, as
revealed by comparing 2-D gels of wild-type and mutant heat-shocked samples and
mass spectrometry analysis of the differentially produced proteins