title: Mutational analysis of human heat-shock transcription factor 1 reveals a regulatory role for oligomerization in DNA-binding specificity.
abstract: HSF (heat-shock transcription factor) trimers bind to the HSE (heat-shock element) regulatory sequence of target genes and regulate gene expression. A typical HSE consists of at least three contiguous inverted repeats of the 5-bp sequence nGAAn. Yeast HSF is able to recognize discontinuous HSEs that contain gaps in the array of the nGAAn sequence; however, hHSF1 (human HSF1) fails to recognize such sites in vitro, in yeast and in HeLa cells. In the present study, we isolated suppressors of the temperature-sensitive growth defect of hHSF1-expressing yeast cells. Intragenic suppressors contained amino acid substitutions in the DNA-binding domain of hHSF1 that enabled hHSF1 to regulate the transcription of genes containing discontinuous HSEs. The substitutions facilitated hHSF1 oligomerization, suggesting that the DNA-binding domain is important for this conformational change. Furthermore, other oligomerization-prone derivatives of hHSF1 were capable of recognizing discontinuous HSEs. These results suggest that modulation of oligomerization is important for the HSE specificity of hHSF1 and imply that hHSF1 possesses the ability to bind to and regulate gene expression via various types of HSEs in diverse cellular processes.
authors.affiliation: Division of Health Sciences, Kanazawa University Graduate School of Medical Science, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Takemori
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Enoki
authors.forename: Noritaka
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Yo
authors.initials: Y
authors.lastname: Fukai
authors.forename: Kaori
authors.initials: K
authors.lastname: Adachi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakurai
mesh_terms: D000595:Amino Acid Sequence; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006367:HeLa Cells; D000076249:Heat Shock Transcription Factors; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013379:Substrate Specificity; D014157:Transcription Factors / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D000076249:Heat Shock Transcription Factors; D014157:Transcription Factors; D004247:DNA