Yamamoto Ayako, Sakurai Hiroshi
Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
Biochem Biophys Res Commun. 2006 Aug 11;346(4):1324-9. doi: 10.1016/j.bbrc.2006.06.057. Epub 2006 Jun 19.
The heat shock transcription factor (HSF) is a key regulator of the heat shock response. In Saccharomyces cerevisiae, the transcription activating ability of Hsf1 is repressed by its DNA-binding domain, but the detailed mechanism by which the inhibitory function is relieved in response to stress remains unknown. In this study, we isolated and characterized three hsf1 mutants with temperature-sensitive mutations in the DNA-binding domain. Two mutations inhibited DNA-binding activity, leading to decreased expression of target genes. The third mutation caused transcriptional defects without affecting DNA binding, and its suppressor mutation was located in a region important for sensing heat shock. These results indicate that the DNA-binding domain regulates both the DNA-binding and transcriptional activities of Hsf1, and suggest that these functions are located within discrete regions of the DNA-binding domain.
热休克转录因子（HSF）是热休克反应的关键调节因子。在酿酒酵母中，Hsf1的转录激活能力受到其DNA结合结构域的抑制，但应激时这种抑制功能得以解除的详细机制仍不清楚。在本研究中，我们分离并鉴定了三个在DNA结合结构域发生温度敏感突变的hsf1突变体。两个突变抑制了DNA结合活性，导致靶基因表达下降。第三个突变导致转录缺陷但不影响DNA结合，其抑制突变位于对热休克感应重要的区域。这些结果表明，DNA结合结构域调节Hsf1的DNA结合和转录活性，并提示这些功能位于DNA结合结构域的不同区域。
