Transcription Factor IIIB 50kDa (TFIIIB50)

BRF2encodes one of the multiple subunits of the RNA polymerase III transcription factor complex required for transcription of genes with promoter elements upstream of the initiation site. The product of this gene, a TFIIB-like factor, is directly recruited to the TATA-box of polymerase III small nuclear RNA gene promoters through its interaction with the TATA-binding protein. BRFU encodes a 419-amino acid protein containing a zinc ribbon domain and a core domain sharing significant homology with TFIIB and BRF1TFIIIB50, as a 50-kD protein that could be eluted with several other proteins from anti-TFIIIB90 (BRF1) immunoprecipitates. Sequence analysis revealed that BRF2 shares 20% identity with TFIIB and BRF1 within its N-terminal 231 amino acids.