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.