Abstract
General transcription factor TFIID is a key component of RNA polymerase II transcription initiation. Human TFIID is a megadalton-sized complex comprising TATA-binding protein (TBP) and 13 TBP-associated factors (TAFs). TBP binds to core promoter DNA, recognizing the TATA-box. We identified a ternary complex formed by TBP and the histone fold (HF) domain-containing TFIID subunits TAF11 and TAF13. We demonstrate that TAF11/TAF13 competes for TBP binding with TATA-box DNA, and also with the N-terminal domain of TAF1 previously implicated in TATA-box mimicry. In an integrative approach combining crystal coordinates, biochemical analyses and data from cross-linking mass-spectrometry (CLMS), we determine the architecture of the TAF11/TAF13/TBP complex, revealing TAF11/TAF13 interaction with the DNA binding surface of TBP. We identify a highly conserved C-terminal TBP-interaction domain (CTID) in TAF13, which is essential for supporting cell growth. Our results thus have implications for cellular TFIID assembly and suggest a novel regulatory state for TFIID function.
Highlights
Eukaryotic gene expression is a highly regulated process which is controlled by a plethora of proteins, arranged in multiprotein complexes including the general transcription factors (GTFs), Mediator and RNA polymerase II (Pol II) (Gupta et al, 2016; Thomas and Chiang, 2006)
We set out to analyze the structure of a putative pentameric TAF11/TAF13/TFIIA/TATA-binding protein (TBP)/DNA complex (Kraemer et al, 2001; Lavigne et al, 1999; Robinson et al, 2005), with the objective to better understand the possible roles of TAF11/TAF13 in TFIID function
TFIIA in human cells is made from two precursor polypeptides, TFIIAab and TFIIAg, with TFIIAab processed in vivo into two separate polypeptides, a and b, by proteolytic cleavage mediated by the protease Taspase1 (Høiby et al, 2007)
Summary
Eukaryotic gene expression is a highly regulated process which is controlled by a plethora of proteins, arranged in multiprotein complexes including the general transcription factors (GTFs), Mediator and RNA polymerase II (Pol II) (Gupta et al, 2016; Thomas and Chiang, 2006). The TFIID component TAF1 was found to associate with the concave DNA-binding surface of TBP via its N-terminal domain (TAF1-TAND), exhibiting TATA-box mimicry (Anandapadamanaban et al, 2013). TAF1-TAND, unstructured in isolation, was found to adopt a three-dimensional structure closely resembling the TATA-element is shape and charge distribution when bound to TBP (Burley and Roeder, 1998; Liu et al, 1998) This interaction is conserved in yeast, Drosophila and human (Anandapadamanaban et al, 2013; Burley and Roeder, 1998; Liu et al, 1998; Mal et al, 2004). We propose a novel, functional state of TFIID in transcription regulation
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