title: Dynamics of the full length and mutated heat shock factor 1 in human cells.
abstract: Heat shock factor 1 is the key transcription factor of the heat shock response. Its function is to protect the cell against the deleterious effects of stress. Upon stress, HSF1 binds to and transcribes hsp genes and repeated satellite III (sat III) sequences present at the 9q12 locus. HSF1 binding to pericentric sat III sequences forms structures known as nuclear stress bodies (nSBs). nSBs represent a natural amplification of RNA pol II dependent transcription sites. Dynamics of HSF1 and of deletion mutants were studied in living cells using multi-confocal Fluorescence Correlation Spectroscopy (mFCS) and Fluorescence Recovery After Photobleaching (FRAP). In this paper, we show that HSF1 dynamics modifications upon heat shock result from both formation of high molecular weight complexes and increased HSF1 interactions with chromatin. These interactions involve both DNA binding with Heat Shock Element (HSE) and sat III sequences and a more transient sequence-independent binding likely corresponding to a search for more specific targets. We find that the trimerization domain is required for low affinity interactions with chromatin while the DNA binding domain is required for site-specific interactions of HSF1 with DNA.
authors.affiliation: INSERM, University Grenoble 1, IAB CRI U823 team 10, La Tronche, France.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Herbomel
authors.forename: Meike
authors.initials: M
authors.lastname: Kloster-Landsberg
authors.forename: Eric G
authors.initials: EG
authors.lastname: Folco
authors.forename: Edwige
authors.initials: E
authors.lastname: Col
authors.forename: Yves
authors.initials: Y
authors.lastname: Usson
authors.forename: Claire
authors.initials: C
authors.lastname: Vourc'h
authors.forename: Antoine
authors.initials: A
authors.lastname: Delon
authors.forename: Catherine
authors.initials: C
authors.lastname: Souchier
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability; D022003:Cell Nucleus Structures / Q000378:metabolism; D005591:Chemical Fractionation; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006367:HeLa Cells; D000076249:Heat Shock Transcription Factors; D018869:Heat-Shock Response / Q000235:genetics; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012313:RNA / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013312:Stress, Physiological; D013347:Subcellular Fractions / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; C490017:Hsf1 protein, mouse; D050505:Mutant Proteins; D014157:Transcription Factors; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D012313:RNA; D004247:DNA