critical role for heat shock transcription factor in establishing a nucleosome-free region over the TATA-initiation site of the yeast HSP82 heat shock gene

• Published in: The EMBO journal 1993-10, Vol.12 (10), p.3931-3945
• Main Authors: Gross, D.S, Adams, C.C, Lee, S, Stentz, B
• Format: Article
• Language: English
• Subjects: Base Sequence; binding proteins; Binding Sites; Biological and medical sciences; chromatin; Deoxyribonuclease I; DNA; dna modification; DNA, Fungal; DNA-Binding Proteins - metabolism; enzyme activity; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; gene expression; Genes. Genome; genetic regulation; heat shock element; heat shock factor; heat shock proteins; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; hsp82 gene; HSP90 Heat-Shock Proteins; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Mutagenesis, Site-Directed; Nucleosomes - metabolism; Phenotype; promoter regions; Promoter Regions, Genetic; Restriction Mapping; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; structural genes; TATA Box; transcription (genetics); Transcription Factors - metabolism; Transcription, Genetic
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1002/j.1460-2075.1993.tb06071.x

Heat shock genes are poised for rapid transcriptional activation in response to environmental stress. A universal structural characteristic of such genes is the presence of a nucleosome-free, DNase I hypersensitive promoter region. Here we investigate the structural and functional effects of mutating HSE1, the preferred heat shock factor (HSF) binding site upstream of the yeast HSP82 gene. In situ deletion or substitution of this sequence reduces both basal and induced transcription by at least two orders of magnitude. Moreover, such mutations lead to a dramatic transition in chromatin structure: the DNase I hypersensitive region is replaced by two stable, sequence-positioned nucleosomes. One of these is centered over the mutated heat shock element, while the other--as revealed by DNase I genomic foot-printing--is precisely positioned in a rotational sense over the TATA-initiation site. Overexpression of yeast HSF strongly suppresses the null phenotype of the induced hsp82-delta HSE1 gene and re-establishes DNase I hypersensitivity over its promoter. Such suppression is mediated through sequence disposed immediately upstream of HSE1 and containing two low affinity heat shock elements. These data imply a critical role for HSF in displacing stably positioned nucleosomes in Saccharomyces cerevisiae and suggest that HSF transcriptionally activates HSP82 at least partly through its ability to alleviate nucleosome repression of the core promoter.