摘要
Objective To investigate the effect of trans-acting factor(s) on rat glutathione S-transferase P1 gene (rGSTP1) transcription regulation in tumor cells.Methods The binding of trans-acting factor(s) to two enhancers of the rGSTP1 gene, glutathione S-transferase P enhancer Ⅰ (GPEI) and glutathione S-transferase P enhancer Ⅱ-1 (GPEⅡ-1), was identified by an electrophoretic mobility shift assay (EMSA). The molecular weight of trans-acting factor was measured in a UV cross-linking experiment. Results Trans-acting factor interacting with the core sequence of GPEI (cGPEI) were found in human cervical adenocarcinoma cell line (HeLa) and rat hepatoma cell line (CBRH7919). These proteins were not expressed in normal rat liver. Although specific binding proteins that bound to GPEⅡ-1 were detected in all three cell types, a 64 kDa binding protein that exists in HeLa and CBRH7919 cells was absent in normal rat liver. Conclusion cGPEI, GPEII specific binding proteins expressed in HeLa and CBRH7919 cells may play an important role in the high transcriptional level of the rGSTP1 gene in tumor cells.
目的 探讨肿瘤细胞中反式作用因子对大鼠谷胱甘肽S 转移酶P1(ratglutathioneS transferaseP1,rGSTP1)基因转录调控的作用。方法 采用凝胶电泳迁移率变更实验检测结合于大鼠谷胱甘肽S 转移酶P1基因上个增强子元件GPEⅠ ,GPEⅡ 1上的反式作用因子 ,DNA 蛋白质紫外交联实验确定反式作用因子的分子量。结果 分析对比不同细胞中结合于GPEI核心序列 (cGPEI)、GPEⅡ 1上特异性核结合蛋白 ,发现HeLa(人宫颈腺癌细胞系 )、CBRH7919(大鼠肝癌细胞系 )细胞中存在的cGPEI特异性结合蛋白及GPEⅡ 1特异性的 6 4kDa结合蛋白在正常大鼠肝细胞中不存在。结论 HeLa、CBRH7919细胞内结合于cGPE ,GPEⅡ上特异性的结合蛋白对rGSTP1基因在肿瘤细胞中的高水平转录起重要的作用。
