Transcriptional repressor of vasoactive intestinal peptide receptor mediates repression through interactions with TFIIB and TFIIEbeta.

The transcriptional repressor for rat vasoactive-intestinal-polypeptide receptor 1 (VIPR-RP) is a recently characterized transcription factor that belongs to a family of proteins, which include components of the DNA replication factor C complex. In this study, I investigated the mechanisms by which VIPR-RP represses transcription. I show here that transcriptional repression by VIPR-RP is mediated by a histone deacetylase-independent mechanism. I provide evidence that VIPR-RP makes direct physical contacts with two proteins of the basal transcription apparatus, the transcription factors TFIIB and TFIIEbeta. The interaction with TFIIB is mediated by the N-terminal 180 amino acids, whereas the interactive domain with TFIIEbeta is located between residues 367 and 527 of VIPR-RP. Using gel mobility-shift assays I demonstrated that interaction between VIPR-RP and TFIIB prevents the recruitment of TFIIB into a DNA-TATA-box-binding protein complex. My results indicate that VIPR-RP mediates transcriptional repression through direct interactions with the general transcription machinery.