:研究c myc对人端粒酶逆转录酶 (htert)启动子的调节作用。方法 :采用Lipofect脂质体转染法将DNA质粒分别转染至肝癌细胞HepG2 、猴肾COS 7细胞和NIH3T3细胞 ,孵育 48h后 ,分别检测其报告基因萤虫素酶活性。结果 :与对照相比 ,载有htert 80 0bp启动子的质粒TERTLuc(80 0 )在肿瘤细胞HepG2 中活性显著增强。外源性转录因子c myc可显著上调htert启动子的表达 ,其激活作用与剂量呈正相关。人工突变c myc结合位点明显降低htert启动子的活性。结论 :c myc可直接激活htert启动子的表达 ,是调节端粒酶活性的重要转录因子。

Objective: To investigate the gene regulation of the promoter of human telomerase reverse transcriptase (htert) by transcription factor c-myc. Methods: The various plasmids were transfected into cell lines NIH3T3, COS-7 and HepG 2 by Lipofect respectively. The plasmids included c-myc expressing plasmid and its control vector, the plasmid TERTLuc(800) harboring 800 bp of htert promoter and TERTLuc(800)DM, which was mutated in c-myc binding sites of TERTLuc(800). The reporter gene luciferase activities were measured 48 hours after transfection. Results: The plasmid TERTLuc(800), generated stronger activity in hepatoma cell line HepG 2. Transcription factor c-myc tran-activated the htert promoter in a dose-dependent manner. In addition, mutation of the c-myc binding sites in the htert promoter decreased its activity by 50%. c-myc up-regulated the htert promoter activity through the c-myc binding sites. Conclusion: Our results indicate that c-myc can trans-activate the htert promoter activity.

R739.5 R730.5

本课题受上海市青年科技启明星计划基金(00QBl4054)资助