The Transcriptional Response of Saccharomyces cerevisiae to Osmotic Shock: Hot1p AND Msn2p/Msn4p ARE REQUIRED FOR THE INDUCTION OF SUBSETS OF HIGH OSMOLARITY GLYCEROL PATHWAY-DEPENDENT GENES

Stefan Hohmann,Johan M Thevelein,Martijn Rep,Marcus Krantz

doi:10.1074/jbc.275.12.8290

Abstract

We have analyzed the transcriptional response to osmotic shock in the yeast Saccharomyces cerevisiae. The mRNA level of 186 genes increased at least 3-fold after a shift to NaCl or sorbitol, whereas that of more than 100 genes was at least 1.5-fold diminished. Many induced genes encode proteins that presumably contribute to protection against different types of damage or encode enzymes in glycerol, trehalose, and glycogen metabolism. Several genes, which encode poorly expressed isoforms of enzymes in carbohydrate metabolism, were induced. The high osmolarity glycerol (HOG) pathway is required for full induction of many but not all genes. The recently characterized Hot1p transcription factor is required for normal expression of a subset of the HOG pathway-dependent responses. Stimulated expression of the genes that required the general stress-response transcription factors Msn2p and Msn4p was also reduced in a hog1 mutant, suggesting that Msn2p/Msn4p might be regulated by the HOG pathway. The expression of genes that are known to be controlled by the mating pheromone response pathway was stimulated by osmotic shock specifically in a hog1 mutant. Inappropriate activation of the mating response may contribute to the growth defect of a hog1 mutant in high osmolarity medium.

Highlights

We have analyzed the transcriptional response to osmotic shock in the yeast Saccharomyces cerevisiae
Stimulated expression of the genes that required the general stress-response transcription factors Msn2p and Msn4p was reduced in a hog1 mutant, suggesting that Msn2p/Msn4p might be regulated by the high osmolarity glycerol (HOG) pathway
The Transcriptional Response to Osmotic Stress Comprises About 5% of All Yeast Genes—The purpose of this genome-wide transcriptional analysis was the identification and classification of genes whose rapid induction by osmotic shock is dependent on the Hog1p kinase and the transcription factors Hot1p and Msn2p/Msn4p

Summary

Introduction

We have analyzed the transcriptional response to osmotic shock in the yeast Saccharomyces cerevisiae. The high osmolarity glycerol (HOG) pathway is required for full induction of many but not all genes. Stimulated expression of the genes that required the general stress-response transcription factors Msn2p and Msn4p was reduced in a hog mutant, suggesting that Msn2p/Msn4p might be regulated by the HOG pathway. The expression of genes that are known to be controlled by the mating pheromone response pathway was stimulated by osmotic shock in a hog mutant. To properly control gene expression, the cell has to sense osmotic changes and transmit the signal to the nucleus. Of Biochemistry, University of Amsterdam, Academic Medical Centre, Meibergdreef 15, NL-1105 AZ Amsterdam, The Netherlands It appears that many if not all eukaryotic cells employ mitogenactivated protein (MAP) kinase pathways for this purpose (3, 6, 7). Protein interaction and phosphotransfer in the HOG pathway and the nuclear translocation process of Hog1p have been studied in great detail (3, 6, 18)

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Results

Conclusion