Regulation of hTERT promoter transcription activity by bHLH family genes

• 1、Faculty of Laboratory Medicine at Chongqing Medical University

Abstract：AIM: To investigate the transcription regulation of the promoter of human telomerase reverse transcriptase (hTERT) by transcription factors c-myc and mad1. METHODS: The various plasmids including wild type hTERT(Tw) or mutant type hTERT(Td) which were harbored with luciferase gene in both, and the expression plasmids of c-myc and mad1, their control vectors were constructed. The plasmids were cotranfected into bladder cancer cell lines T24, EJ and control cells COS-7, fibrocytes cells NIH3T3 by DOTAP in various combining manner, respectively. The reporter gene luciferase activities of various group were measured 48 hours after transfection. RESULTS: The luciferase activities of T24 and EJ cells treated with Tw were much higher than that of in COS-7 and NIH3T3, and higher than that of T24 and EJ cells treated with Td. In bladder cancer T24 and EJ cells, transcription factor c-myc and mad1 could positively and negatively regulate Tw expression in a dose-dependent manner respectively. However, the effects of c-myc and mad1 on Td were completely opposite to Tw . Combining with c-myc and mad1 would down-regulate the Tw expression. CONCLUSION: c-myc and mad1 could directly regulate the transcription activity of hTERT promoter in bladder cancer cell, and the effects might highly depend on the conservative E-box sequence CACGTG.

Keywords： c-myc mad1 hTERT promoter gene regulation