Ethanol Stress Response in the mRNA Flux of Saccharomyces cerevisiae

Post-transcriptional regulation as well as transcriptional regulation plays an important role in the expression of genes under stressed conditions in Saccharomyces cerevisiae. Under stressed conditions caused by heat shock or ethanol, yeast cells alter not only their transcriptional patterns but also the types of mRNA to be exported from the nucleus in order to adapt rapidly to the stress. Under heat-shocked conditions at 42 degrees C, bulk poly (A)(+) mRNA accumulates in the nucleus, whereas stress-induced transcripts such as HSP mRNAs are efficiently exported. Ethanol stress also causes nuclear accumulation of bulk poly (A)(+) mRNA, but elicits a different response regarding the transport of HSP mRNAs. Other differences between the heat shock response and the ethanol stress response were observed in the nuclear processing of transcripts and in cytosolic mRNA flux. This review outlines the regulation of yeast gene expression at the mRNA processing and nuclear export steps under ethanol stressed conditions, and discusses how to improve the capabilities of brewer's yeast cells.