In vitro activation of heat shock transcription factor by 4-hydroxynonenal.
In the activation of eukaryotic heat shock genes, the acquisition of a binding ability to specific DNA sequence by a transcriptional activator, heat shock factor (HSF), is believed to be a crucial step. The induction of this new DNA binding activity of HSF is also obtained in a cell-free system (in vitro activation) by hyperthermia or at physiological temperature by calcium ions, low pH, urea, or non-ionic detergent. We report here the in vitro activation of HSF by treating at 0 degrees C a HeLa cell-free system with the aldehyde 4-hydroxynonenal (HNE), a highly cytotoxic product of lipid peroxidation. The in vitro activation of HSF by HNE occurred only if some components of the cell-free system were not sedimented at 100,000 x g. The reason for this is unclear but the release of active HSF from nuclei of unshocked cells and the involvement of Ca2+ contained in the mitochondria and ER have been excluded. Although HNE is known to be a sulfhydryl blocking agent, the results obtained with N-ethylmaleimide suggest that different mechanisms might be involved in the in vitro activation of HSF by HNE.
Cajone
F
F
Istituto di Patologia Generale, 'Università degli Studi di Milano, Italy.
Crescente
M
M
D000447:Aldehydes / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D002474:Cell-Free System; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics; D006358:Hot Temperature; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D000447:Aldehydes; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D004247:DNA; C027576:4-hydroxy-2-nonenal; D005033:Ethylmaleimide; D002118:Calcium