About this Journal Submit a Manuscript Table of Contents
Comparative and Functional Genomics
Volume 5 (2004), Issue 5, Pages 419-431
http://dx.doi.org/10.1002/cfg.415
Research article

Genome-Wide Analysis of the Effects of Heat Shock on a Saccharomyces cerevisiae Mutant With a Constitutively Activated cAMP-Dependent Pathway

1Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD, UK
2School of Biological Sciences, University of Manchester, The Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
3Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK
4Michael Barber Centre for Mass Spectrometry, Department of Chemistry, UMIST, PO Box 88, Manchester M60 1QD, UK
5Department of Computer Science, University of Exeter, North Park Road, Exeter EX4 4QF, UK

Received 23 February 2004; Revised 7 June 2004; Accepted 17 June 2004

Copyright © 2004 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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 30℃ to 50℃ 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 pde2Δ 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.