Tsutsumi-Ishii Y, Tadokoro K, Hanaoka F, Tsuchida N
Department of Molecular Cellular Oncology and Microbiology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
Cell Growth Differ. 1995 Jan;6(1):1-8.
Recent studies have demonstrated that mutation of the p53 gene caused a gain of new functions such as transforming activation, binding to heat shock cognate protein 70 and/or transactivation of a variety of promoters. In the course of seeking the biochemical basis for the gain of these functions, we have noticed the correlation between transforming activity of different mutated p53 genes and their transactivational activity on the human heat shock protein 70 promoter. Analysis of 5' deletion constructs of the heat shock protein 70 promoter showed that some specific elements within the heat shock domain containing two heat shock elements (HSEs) could respond to mutant p53 species but not basic promoter elements such as the TATA box, CCAAT box, and GC box. Subsequently, we identified the HSE as a responsive element using reporter constructs of minimal promoter containing synthetic proximal HSE, distal HSE, or GC/CCAAT box. Further analysis using in vitro mutagenesis of HSE suggests that HSE with heat shock factor binding ability is required for transactivation of the heat shock protein 70 promoter by mutated p53 genes.
最近的研究表明，p53基因的突变会导致新功能的获得，如转化激活、与热休克同源蛋白70结合和/或多种启动子的反式激活。在寻找这些功能获得的生化基础的过程中，我们注意到不同突变型p53基因的转化活性与其对人热休克蛋白70启动子的反式激活活性之间的相关性。对热休克蛋白70启动子的5'缺失构建体的分析表明，热休克结构域内包含两个热休克元件（HSEs）的一些特定元件可对突变型p53作出反应，但对基本启动子元件如TATA盒、CCAAT盒和GC盒无反应。随后，我们使用含有合成近端HSE、远端HSE或GC/CCAAT盒的最小启动子的报告构建体，将HSE鉴定为反应元件。使用HSE的体外诱变进行的进一步分析表明，具有热休克因子结合能力的HSE是突变型p5基因反式激活热休克蛋白70启动子所必需的。
