Transcription Factor IIIB 90kDa (TFIIIB90)

BRF1 encodes one of the three subunits of the RNA polymerase III transcription factor complex. This complex plays a central role in transcription initiation by RNA polymerase III on genes encoding tRNA, 5S rRNA, and other small structural RNAs. The gene product belongs to the TF2B family. Three alternatively spliced variants encoding three different isoforms, that function at different promoters transcribed by RNA polymerase III, have been identified. A transcript encoding a fourth isoform has not yet been completely characterized.Sequence analysis revealed that the 675-amino acid TAF3B2 protein contains a high mobility group protein-2 (HMG2)-related region in the highly charged C-terminal half of the protein and a sequence related to GTF2B in the N terminus.