A new regulatory domain on the TATA-binding protein.

Recognition of the TATA box by the TATA-binding protein (TBP) is a highly regulated step in RNA polymerase II-dependent transcription. Several proteins have been proposed to regulate TBP activity, yet the TBP domains responsive to all these regulators have not been defined. Here we describe a new class of TBP mutants that increase transcription from core promoters in vivo. The majority of these mutations alter amino acids that cluster tightly on the TBP surface, defining a new TBP regulatory domain. The mutant TBP proteins are defective for binding the transcriptional regulator yNC2, are resistant to inhibition by yNC2 in vitro and exhibit allele-specific genetic interactions with yNC2. These results provide strong biochemical and genetic evidence that TBP is directly repressed in vivo, and define a new TBP domain important for transcriptional regulation.