Direct sensing of heat and oxidation by Drosophila heat shock transcription factor.
The heat shock transcription factor HSF activates expression of its target genes in response to elevated temperatures and chemical or physiological stress. A key step in the activation process involves the formation of HSF homotrimers, leading to high-affinity DNA binding. The mechanism by which HSF trimerization and DNA binding is regulated by stress signals has remained elusive. Here, we report that trimerization and DNA binding of purified Drosophila HSF can be directly and reversibly induced in vitro by heat shock temperatures in the physiological range and by an oxidant, hydrogen peroxide. Other inducers of the heat shock response, including salicylate, dinitrophenol, ethanol, and arsenite, have no effect on HSF trimerization in vitro, indicating that these inducers act by indirect mechanisms.
Laboratory of Molecular Cell Biology, National Cancer Institute, Bethesda, Maryland 20892-4255, USA.
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Zhong
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Orosz
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Wu
D000222:Adaptation, Physiological; D000818:Animals; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000502:physiology*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000502:physiology*; D005786:Gene Expression Regulation; D000076249:Heat Shock Transcription Factors; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019476:Insect Proteins / Q000737:chemistry / Q000502:physiology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D000076249:Heat Shock Transcription Factors; C053134:Hsf protein, Drosophila; D019476:Insect Proteins; D014157:Transcription Factors; D004247:DNA; D006861:Hydrogen Peroxide