Alternative titles; symbols
HGNC Approved Gene Symbol: BRF2
Cytogenetic location: 8p11.23 Genomic coordinates (GRCh38): 8:37,843,268-37,849,861 (from NCBI)
By database searching with the sequence of BRF1 (604902) as query, Schramm et al. (2000) identified BRF2, which they called BRFU, and cloned the corresponding cDNA from a total HeLa cell cDNA library. BRFU encodes a 419-amino acid protein containing a zinc ribbon domain and a core domain sharing significant homology with TFIIB (189963) and BRF1.
By peptide sequencing, Teichmann et al. (2000) identified BRF2, which they designated TFIIIB50, as a 50-kD protein that could be eluted with several other proteins from anti-TFIIIB90 (BRF1; 604902) immunoprecipitates. Sequence analysis revealed that BRF2 shares 20% identity with TFIIB and BRF1 within its N-terminal 231 amino acids.
Schramm et al. (2000) found that antibodies directed against BRFU were inhibitory in an in vitro translation assay dependent upon the U6 promoter. Cabart and Murphy (2001) provided evidence that BRFU is involved in the nucleation of a polymerase III-specific small nuclear RNA (snRNA) transcription initiation complex. Using recombinant proteins and HeLa cell nuclear extracts in GST pull-down and electrophoretic gel mobility assays, they determined that BRFU does not directly bind DNA; rather, it interacts with the TATA-binding protein (TBP; 600075), and these then bind cooperatively to the polymerase III promoter region of snRNA. The TBP/BRFU complex does not appear to have strict requirements for sequence motifs outside the TATA box. With use of deletion and point mutations, they determined that arg235 and phe250 of TBP, and repeat 2 of the BRFU core domain, are necessary for complex formation with DNA. BRFU also forms a stable complex on the TATA box of the polymerase II-specific adenovirus major late promoter.
Using an in vitro transcription reconstitution assay, Teichmann et al. (2000) determined that BRF2 forms a stable complex with TBP and TFIIIB150 (BDP1; 607012), as well as with other associated proteins, to confer promoter specificity to RNA polymerase III for the transcription of U6 and 7SK genes.
The International Radiation Hybrid Mapping Consortium mapped the BRF2 gene to chromosome 8 (RH101040).
Cabart, P., Murphy, S. BRFU, a TFIIB-like factor, is directly recruited to the TATA-box of polymerase III small nuclear RNA gene promoters through its interaction with TATA-binding protein. J. Biol. Chem. 276: 43056-43064, 2001. [PubMed: 11564744] [Full Text: https://doi.org/10.1074/jbc.M108515200]
Schramm, L., Pendergrast, P. S., Sun, Y., Hernandez, N. Different human TFIIIB activities direct RNA polymerase III transcription from TATA-containing and TATA-less promoters. Genes Dev. 14: 2650-2663, 2000. [PubMed: 11040218] [Full Text: https://doi.org/10.1101/gad.836400]
Teichmann, M., Wang, Z., Roeder, R. G. A stable complex of a novel transcription factor IIB-related factor, human TFIIIB50, and associated proteins mediate selective transcription by RNA polymerase III of genes with upstream promoter elements. Proc. Nat. Acad. Sci. 97: 14200-14205, 2000. [PubMed: 11121026] [Full Text: https://doi.org/10.1073/pnas.97.26.14200]