Heat Shock Transcription Factor 1 Opens Chromatin Structure of Interleukin-6 Promoter to Facilitate Binding of an Activator or a Repressor

Sachiye Inouye, Mitsuaki Fujimoto, Tamami Nakamura, Eiichi Takaki, Naoki Hayashida, Tsonwin Hai, Akira Nakai
2007 Journal of Biological Chemistry  
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
more » ... Lack of HSF1 inhibited LPS-induced in vivo binding of an activator NF-B and a repressor ATF3 to IL-6 promoter. Neither NF-B 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. . 2 The abbreviations used are: HSF, heat shock transcription factor; ChIP, chromatin immunoprecipitation; HSE, heat shock element; Hsp, heat shock protein; LPS, lipopolysaccaride; MEF, mouse embryo fibroblasts; CBP, CREB-binding protein; GFP, green fluorescent protein; pfu, plaque forming unit.
doi:10.1074/jbc.m704471200 pmid:17766920 fatcat:2rntbppfqfh63ppkb5hahuwejy