TFIIA regulates TBP and TFIID dimers.
Dimerization of the TATA-binding protein (TBP) through its DNA-binding domain blocks TBP from accessing DNA and prevents unregulated gene expression. TFIIA plays a central role in loading TBP and its multisubunit counterpart TFIID onto promoter DNA, and it is therefore a candidate for regulating TBP/TFIID dimerization. Here, we show that TFIIA promotes the dissociation of TBP dimers directly and in doing so accelerates the kinetics of DNA binding. TFIID dimer dissociation was found to be slow and rate limiting in DNA binding. TFIIA induced a rapid dissociation of TFIID dimers, allowing TFIID to readily load onto promoter DNA. Together, these results suggest a novel mechanism by which TFIIA assists in regulating gene expression.
Coleman
R A
RA
Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16802, USA.
Taggart
A K
AK
Burma
S
S
Chicca
J J
JJ
Pugh
B F
BF
D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D005786:Gene Expression Regulation; D006801:Humans; D007700:Kinetics; D008957:Models, Genetic; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D016385:TATA Box; D035181:TATA-Box Binding Protein; D035561:Transcription Factor TFIIA; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000737:chemistry / Q000378:metabolism*
D004268:DNA-Binding Proteins; D035181:TATA-Box Binding Protein; D035561:Transcription Factor TFIIA; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D004247:DNA