<p>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.</p> <p>DNA arrays were used to measure changes in transcript levels as yeast cells responded to temperature shocks. The number of genes upregulated by temperature shifts from
30 ℃ to 37℃ or 45℃ was correlated with the severity of the stress. Pre-adaptation
of cells, by growth at 37 ℃ previous to the 45℃ shift, caused a decrease in the
number of genes related to this response. Heat shock also caused downregulation of a
set of genes related to metabolism, cell growth and division, transcription, ribosomal
proteins, protein synthesis and destination. Probably all of these responses combine
to slow down cell growth and division during heat shock, thus saving energy for
cell rescue. The presence of putative binding sites for Xbp1p in the promoters of
these genes suggests a hypothetical role for this transcriptional repressor, although
other mechanisms may be considered. The response to cold shock (4℃) affected a
small number of genes, but the vast majority of those genes induced by exposure to
4 ℃ were also induced during heat shock; these genes share in their promoters <italic>cis</italic>-regulatory
elements previously related to other stress responses.</p>
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Comp Funct Genomics. 2003 Jul; 4(4):366-375