MUTATIONAL ANALYSIS OF THE HUMAN ENDOGENOUS ERV9 PROVIRUSES PROMOTER REGION

ERV9 is a low repeated family of human endogenous retroviral elements whose expression is mainly detectable in undifferentiated embryonal ca rcinoma NT2/D1 cells. To define all the elements required for the corr ect transcription activity of the ERV9 promoter and to establish a pre cise correlation between the elements important for basal transcriptio n, we have systematically analyzed the in vivo and in vitro transcript ional activity of many different ERV9 promoter mutants, including a se ries of linker-scanning mutations across the promoter region. We repor t here that the ERV9 promoter contains two elements controlling the se lection of the correct start sites, a TATA box and an Inr-like region; the concerted action of both elements is necessary for faithful trans cription. Finally, using a series of GAL4 protein fusion constructs in cotransfection experiments, we demonstrated that various transcriptio n factors can synergistically induce a high level of transcription whe n bound to an ERV9 DNA promoter. (C) 1994 Academic Press, Inc.