Transcriptional regulation and binding of heat shock factor 1 and heat shock factor 2 to 32 human heat shock genes during thermal stress and differentiation.
Transcription of mammalian heat shock genes can be regulated by heat shock factors (HSF) 1 and 2. Although it has been shown previously that these factors respond to distinct stimuli, a broad analysis of the induction and function of these factors in living cells has not been performed. In our study, we assayed binding of human HSF1 and HSF2 at the promoters of 32 genes identified through LocusLink as heat shock genes in response to elevated temperature and hemin-induced differentiation in human K562 erythroleukemic cells using the chromatin immunoprecipitation technique. We also measured the induced expression of these genes under these 2 conditions. We found that 17 of the 32 genes were transcriptionally induced during heat shock, and HSF1 binding was detected at 15 of the 17 promoters. Nearly all the genes induced by heat shock were also induced to a lesser degree during hemin treatment. However, some genes were induced significantly more during hemin treatment than during heat shock. A new finding is that HSF1 and HSF2 bind to the same targets, but HSF1 binding is activated more by heat than by hemin treatment, and HSF2 binding is only activated by hemin treatment and not by heat. This technology also identified previously unknown HSF1 binding sites near genes that were previously shown to be heat inducible that may contribute to gene-specific regulation.
Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA.
Nathan D
ND
Trinklein
Will C
WC
Chen
Robert E
RE
Kingston
Richard M
RM
Myers
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics* / Q000502:physiology; D002843:Chromatin / Q000276:immunology / Q000302:isolation & purification; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D030541:Databases, Genetic; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000235:genetics / Q000502:physiology; D006427:Hemin / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D007438:Introns / Q000235:genetics; D020014:K562 Cells; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D002843:Chromatin; D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; C057725:HSPB1 protein, human; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D014157:Transcription Factors; C070389:HSF2 protein, human; D006427:Hemin; D004247:DNA