In vivo and in vitro analyses of Myc for differential promoter activities of the human telomerase (hTERT) gene in normal and tumor cells.

Induction of the catalytic subunit of human telomerase, hTERT, plays a critical role in the activation of telomerase during tumorigenesis. Here, we isolate the hTERT gene promoter and define the functional promoter region, which is inactive in normal cells but active in tumor cells. Myc directly interacts with the hTERT promoter and activates its transcription both in vivo and in vitro. Activation or repression of Myc can alter hTERT promoter activities in normal or tumor cells. Furthermore, we detect high levels of Myc protein in tumor cells compared with normal cells. The ability of Myc to modulate the activity of the hTERT promoter and, hence, the telomerase enzyme may contribute to its ability to promote tumor formation. Copyright 1999 Academic Press.