title: Heat shock transcription factor 1 opens chromatin structure of interleukin-6 promoter to facilitate binding of an activator or a repressor.
abstract: Heat shock transcription factor 1 (HSF1) not only regulates expression of heat shock genes in response to elevated temperature, but is also involved in developmental processes by regulating genes such as cytokine genes. However, we did not know how HSF1 regulates non-heat shock genes. Here, we show that constitutive HSF1 binding to the interleukin (IL)-6 promoter is necessary for its maximal induction by lipopolysaccharide (LPS) stimulation in mouse embryo fibroblasts and peritoneal macrophages. Lack of HSF1 inhibited LPS-induced in vivo binding of an activator NF-kappaB and a repressor ATF3 to IL-6 promoter. Neither NF-kappaB nor ATF3 binds to the IL-6 promoter in unstimulated HSF1-null cells even if they were overexpressed. Treatment with histone deacetylase inhibitor or a DNA methylation inhibitor restored LPS-induced IL-6 expression in HSF1-null cells, and histone modification enzymes were recruited on the IL-6 promoter in the presence of HSF1. Consistently, chromatin structure of the IL-6 promoter in the presence of HSF1 was more open than that in its absence. These results indicate that HSF1 partially opens the chromatin structure of the IL-6 promoter for an activator or a repressor to bind to it, and provides a novel mechanism of gene regulation by HSF1.
authors.affiliation: Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube, Japan.
authors.forename: Sachiye
authors.initials: S
authors.lastname: Inouye
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Tamami
authors.initials: T
authors.lastname: Nakamura
authors.forename: Eiichi
authors.initials: E
authors.lastname: Takaki
authors.forename: Naoki
authors.initials: N
authors.lastname: Hayashida
authors.forename: Tsonwin
authors.initials: T
authors.lastname: Hai
authors.forename: Akira
authors.initials: A
authors.lastname: Nakai
mesh_terms: D051700:Activating Transcription Factor 3 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002843:Chromatin / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D000076249:Heat Shock Transcription Factors; D006657:Histones / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D051700:Activating Transcription Factor 3; C103002:Atf3 protein, mouse; D002843:Chromatin; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006657:Histones; C490017:Hsf1 protein, mouse; D015850:Interleukin-6; D016328:NF-kappa B; D014157:Transcription Factors; D004247:DNA