Hung J J, Cheng T J, Chang M D, Chen K D, Huang H L, Lai Y K
Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
J Cell Biochem. 1998 Oct 1;71(1):21-35.
Exposure of 9L rat brain tumor cells to 40-100 microM CdCl2 for 2 h leads to an induction of a wide spectrum of heat shock proteins (HSPs). We have demonstrated that induction of the 70-kDa HSP (HSP70) and enhanced expression of its cognate (HSC70) by cadmium are concentration dependent and that the induction kinetics of these HSP70s are different. The increased synthesis of the HSP70s is accompanied by the increase in hsp70 and hsc70 mRNA levels, indicative of transcriptional regulation of the heat shock genes. Electrophoretic mobility shift assay (EMSA) using probes encompassing heat shock element (HSE), TATA, GC, and CCAAT boxes derived from the promoter regions of the heat shock genes shows distinguished binding patterns between hsp70 and hsc70 genes in both control and cadmium-treated cells. The results indicate that, in addition to the HSEs, the basal transcription elements are important in the regulation of the heat shock genes. The binding patterns of the corresponding transcription factors of these elements are examined by EMSA by using extended promoter fragments from respective heat shock genes with sequential addition of excess oligonucleotides encompassing individual transcription elements. Taken together, our results show that the differential induction of hsp70 and hsc70 involves multiple transcription factors that interact with HSE, TATA, GC, and CCAAT boxes.
将9L大鼠脑肿瘤细胞暴露于40 - 100微摩尔氯化镉中2小时会导致多种热休克蛋白（HSPs）的诱导。我们已经证明，镉对70 kDa热休克蛋白（HSP70）的诱导及其同源蛋白（HSC70）表达的增强是浓度依赖性的，并且这些HSP70的诱导动力学是不同的。HSP70s合成的增加伴随着hsp70和hsc70 mRNA水平的升高，这表明热休克基因存在转录调控。使用包含来自热休克基因启动子区域的热休克元件（HSE）、TATA、GC和CCAAT框的探针进行电泳迁移率变动分析（EMSA）显示，在对照细胞和镉处理细胞中，hsp70和hsc70基因之间的结合模式有所不同。结果表明，除了HSEs之外，基础转录元件在热休克基因的调控中也很重要。通过使用来自各个热休克基因的延伸启动子片段，并依次添加包含各个转录元件的过量寡核苷酸，通过EMSA检测这些元件相应转录因子的结合模式。综上所述，我们的结果表明，hsp70和hsc70的差异诱导涉及与HSE、TATA、GC和CCAAT框相互作用的多种转录因子。
