Brf1 Background Information Brf1, a component of the S. cerevisiae RNA polymerase III transcription
factor, TFIIIB, functions in recruitment of RNA polymerase III to the promoter for multiple rounds of transcription. Brf1 precisely positions TFIIIB on the upstream promoter-less DNA by creating stable protein-protein interactions with TATA-binding protein (TBP), another component of TFIIIB. In addition, Brf1 stimulates opening of the promoter, demonstrated by the fact that a deletion in the N-terminal region of Brf1 blocks opening of the promoter past the transcriptional start site. The Ty3 retrovirus-like elements preferentially insert at the initiation sites of genes transcribed by RNA polymerase III. The Brf1 subunit mediates targeting of Ty3 elements to these genes and is necessary for their integration. Brf1 specifically binds to the C34 subunit of RNA polymerase III and the TAU135 subunit of TFIIIC.
