Regulation of thermotolerance by stress-induced transcription factors in Saccharomyces cerevisiae.
The heat shock transcription factor Hsf1 and the general stress transcription factors Msn2 and Msn4 (Msn2/4) are major regulators of the heat shock response in Saccharomyces cerevisiae. Here, we show that transcriptional activation of their target genes, including HSP104, an antistress chaperone gene, is obligatory for thermotolerance. Although Hsf1 activity might be necessary before the exposure of cells to high temperature, severe heat shock induced the binding of hyperphosphorylated Hsf1 to its target promoters. However, promoter-bound, phosphorylated Hsf1 was inactive for transcription because RNA polymerase II was inactive at high temperatures. Rather, our results suggest that Hsf1 activates the transcription of most of its target genes during the recovery period following severe heat shock. This delayed upregulation by Hsf1, which would be induced by misfolded proteins that accumulate in severely heat-shocked cells, is required for the resumption of normal cell growth. In contrast, the factors Msn2/4 were not involved in the delayed upregulation of genes and were dispensable for cell growth during the recovery period, suggesting that they play a role before the exposure to high temperature. These results show that Hsf1 and Msn2/4 act differentially before and after exposure to extreme temperatures to ensure cell survival and growth.
Yamamoto
Noritaka
N
Division of Health Sciences, Kanazawa University Graduate School of Medical Science, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
Maeda
Yuka
Y
Ikeda
Aya
A
Sakurai
Hiroshi
H
D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D017930:Genes, Reporter; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response; D011401:Promoter Regions, Genetic; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C067168:HSF1 protein, S cerevisiae; D006360:Heat-Shock Proteins; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C070972:HsP104 protein, S cerevisiae