title: Domain-wide displacement of histones by activated heat shock factor occurs independently of Swi/Snf and is not correlated with RNA polymerase II density.
abstract: We show that histone-DNA interactions are disrupted across entire yeast heat shock genes upon their transcriptional activation. At HSP82, nucleosomal disassembly spans a domain of approximately 3 kb, beginning upstream of the promoter and extending through the transcribed region. A kinetic analysis reveals that histone H4 loses contact with DNA within 45 s of thermal upshift. Nucleosomal reassembly, prompted by temperature downshift, is also rapid, detectable within 60 s. Prior to their eviction, promoter-associated histones are transiently hyperacetylated, while those in the coding region are not. An upstream activation sequence mutation that weakens the binding of heat shock factor obviates domain-wide remodeling, while deletion of the TATA box that nearly abolishes transcription is permissive to 5'-end remodeling. The Swi/Snf complex is rapidly recruited to HSP82 upon heat shock. Nonetheless, domain-wide remodeling occurs efficiently in Swi/Snf mutants despite a sixfold reduction in transcription; it is also seen in gcn5Delta, set1Delta, and paf1Delta mutants. Contrary to current models, we demonstrate that a high density of RNA polymerase (Pol) is insufficient to elicit histone displacement. This finding suggests that histone eviction is modulated by factors that are not linked to elongating Pol II. It further suggests that histone depletion plays a causal role in mediating vigorous transcription in vivo and is not merely a consequence of it.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, 71130-3932, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Jorge
authors.initials: J
authors.lastname: Herrera-Diaz
authors.forename: David S
authors.initials: DS
authors.lastname: Gross
mesh_terms: D020413:3' Untranslated Regions; D000107:Acetylation; D001483:Base Sequence; D042002:Chromatin Assembly and Disassembly; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response; D006657:Histones / Q000378:metabolism*; D007700:Kinetics; D009707:Nucleosomes / Q000378:metabolism; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D020413:3' Untranslated Regions; D004271:DNA, Fungal; C074510:HSP82 protein, S cerevisiae; D018841:HSP90 Heat-Shock Proteins; D006657:Histones; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012319:RNA Polymerase II