General Transcription Factor 3B 90-kD Subunit

**Semantic type:** Amino Acid, Peptide, or Protein|Biologically Active Substance

**Definition:** Encoded by human BRF1 Gene (TFIIB Family), alternative isoforms 1 (677-aa, 74-kD), 2 (134-aa, altered N- and C-termini), 3 (473-aa, shorter N-terminus), and 4 (242-aa) of General Transcription Factor 3B 90-kD Subunit function at different promoters on tRNA, 5S rRNA, and other small RNA genes. Related to GTF2B (N-terminus), GTF3B contains a highly charged region and HMG2-related region. Essential for transcription initiation, GTF3B (C-terminus) binds TBP (collectively, TFIIIB) as one of three RNA polymerase III transcription factor subunits. Following GTF3A or GTF3C recognition of promoter elements, GTF3B and RNA polymerase III bind sequentially. (NCI)

**Synonyms:** - B-Related Factor 1 - BRF - BRF1 - BRF1 Homolog - BRF1 Homolog Subunit of RNA Polymerase III Transcription Initiation Factor IIIB - GTF3B - GTF3B 90-kD Subunit - General Transcription Factor IIIB 90kD Subunit - TAF3B2 - TAF3C - TAFIII90 - TATA Box Binding Protein (TBP)-Associated Factor 3C - TATA Box Binding Protein (TBP)-Associated Factor RNA Polymerase III Subunit 2 - TATA Box-Binding Protein-Associated Factor RNA Polymerase III Subunit 2 - TBP-Associated Factor RNA Polymerase III 90kD - TF3B90 - TFIIIB90 - Transcription Factor IIIB 90-kD Subunit - Transcription Initiation Factor IIIB - hBRF