The Saccharomyces cerevisiae RNA polymerase III recruitment factor subunits Brf1 and Bdp1 impose a strict sequence preference for the downstream half of the TATA box.
Association of the TATA-binding protein (TBP) with its cognate site within eukaryotic promoters is key to accurate and efficient transcriptional initiation. To achieve recruitment of Saccharomyces cerevisiae RNA polymerase III, TBP is associated with two additional factors, Brf1 and Bdp1, to form the initiation factor TFIIIB. Previous data have suggested that the structure or dynamics of the TBP-DNA complex may be altered upon entry of Brf1 and Bdp1 into the complex. We show here, using the altered specificity TBP mutant TBPm3 and an iterative in vitro selection assay, that entry of Brf1 and Bdp1 into the complex imposes a strict sequence preference for the downstream half of the TATA box. Notably, the selected sequence (TGTAAATA) is a perfect match to the TATA box of the RNA polymerase III-transcribed U6 small nuclear RNA (SNR6) gene. We suggest that the selected T*A base pair step at the downstream end of the 8 bp TBP site may provide a DNA flexure that promotes TFIIIB-DNA complex formation.
Tsihlis
Nick D
ND
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
Grove
Anne
A
D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D016385:TATA Box; D035181:TATA-Box Binding Protein / Q000235:genetics; D035361:Transcription Factor TFIIIB / Q000378:metabolism*
C090956:BRF1 protein, S cerevisiae; C474805:Bdp1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D021122:Protein Subunits; D012342:RNA, Small Nuclear; C115017:SPT15 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D035361:Transcription Factor TFIIIB; C405486:U6 small nuclear RNA; D004247:DNA