A Basal Transcription Factor That Activates or Represses Transcription

We have identified an activity that is required for transcription of downstream promoter element (DPE)-containing core promoters in vitro. The purified factor was found to be the Drosophila homolog of the transcriptional repressor known as NC2 or Dr1-Drap1. Purified recombinant dNC2 activates DPE-driven promoters and represses TATA-driven promoters. A mutant version of dNC2 can activate DPE promoters but is unable to repress TATA promoters. Thus, the activation and repression functions are distinct. These studies reveal that NC2 (Dr1-Drap1) is a bifunctional basal transcription factor that differentially regulates gene transcription through DPE or TATA box motifs.