Mutational analysis of BTAF1-TBP interaction: BTAF1 can rescue DNA-binding defective TBP mutants.
The BTAF1 transcription factor interacts with TATA-binding protein (TBP) to form the B-TFIID complex, which is involved in RNA polymerase II transcription. Here, we present an extensive mapping study of TBP residues involved in BTAF1 interaction. This shows that residues in the concave, DNA-binding surface of TBP are important for BTAF1 binding. In addition, BTAF1 interacts with residues in helix 2 on the convex side of TBP as assayed in protein-protein and in DNA-binding assays. BTAF1 drastically changes the TATA-box binding specificity of TBP, as it is able to recruit DNA-binding defective TBP mutants to both TATA-containing and TATA-less DNA. Interestingly, other helix 2 interacting factors, such as TFIIA and NC2, can also stabilize mutant TBP binding to DNA. In contrast, TFIIB which interacts with a distinct surface of TBP does not display this activity. Since many proteins contact helix 2 of TBP, this provides a molecular basis for mutually exclusive TBP interactions and stresses the importance of this structural element for eukaryotic transcription.
Klejman
Marcin P
MP
Department of Physiological Chemistry, Division of Biomedical Genetics, University Medical Center Utrecht Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
Zhao
Xuemei
X
van Schaik
Frederik M A
FM
Herr
Winship
W
Timmers
H Th Marc
HT
D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism; D016385:TATA Box; D035381:TATA-Binding Protein Associated Factors / Q000378:metabolism*; D035181:TATA-Box Binding Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D035561:Transcription Factor TFIIA / Q000378:metabolism; D035362:Transcription Factor TFIID / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
C109035:BTAF1 protein, human; D010750:Phosphoproteins; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D035561:Transcription Factor TFIIA; D035362:Transcription Factor TFIID; D014157:Transcription Factors; C075995:down-regulator of transcription 1; D004247:DNA