Li Ning, Zhang Le-Min, Zhang Ke-Qin, Deng Jing-Shi, Prändl Ralf, Schöffl Fritz
Zentrum fur Molekularbiologie der Pflanzen-Allgemeine Genetik, Eberhard-Karls-Universitat Tubingen, 72076 Tubingen, Germany.
Acta Biochim Biophys Sin (Shanghai). 2006 May;38(5):356-62. doi: 10.1111/j.1745-7270.2006.00170.x.
Heat shock factor-DNA interaction is critical for understanding the regulatory mechanisms of stress-induced gene expression in eukaryotes. In this study, we analyzed the in vivo binding of yeast heat shock factor (HSF) to the promoters of target genes ScSSA1, ScSSA4, HSP30 and HSP104, using chromatin immunoprecipitation. Previous work suggested that yeast HSF is constitutively bound to DNA at all temperatures. Expression of HSF target genes is regulated at the post-transcriptional level. However, our results indicated that HSF does not bind to the promoters of ScSSA4 and HSP30 at normal temperature (23 degrees C). Binding to these promoters is rapidly induced by heat stress at 39 degrees C. HSF binds to ScSSA1 and HSP104 promoters under non-stress conditions, but at a low level. Heat stress rapidly leads to a notable increase in the binding of HSF to these two genes. The kinetics of the level of HSF-promoter binding correlate well with the expression of target genes, suggesting that the expression of HSF target genes is at least partially the result of HSF-promoter binding stability and subsequent transcription stimulation.
热休克因子与DNA的相互作用对于理解真核生物中应激诱导基因表达的调控机制至关重要。在本研究中，我们使用染色质免疫沉淀技术分析了酵母热休克因子（HSF）在体内与靶基因ScSSA1、ScSSA4、HSP30和HSP104启动子的结合情况。先前的研究表明，酵母HSF在所有温度下都与DNA组成性结合。HSF靶基因的表达在转录后水平受到调控。然而，我们的结果表明，在常温（23摄氏度）下HSF不与ScSSA4和HSP30的启动子结合。在39摄氏度的热应激下，与这些启动子的结合被迅速诱导。在非应激条件下HSF与ScSSA1和HSP104启动子结合，但水平较低。热应激迅速导致HSF与这两个基因的结合显著增加。HSF-启动子结合水平的动力学与靶基因的表达密切相关，表明HSF靶基因的表达至少部分是HSF-启动子结合稳定性及随后转录刺激的结果。
