A Human TATA Binding Protein-Related Protein with Altered DNA Binding Specificity Inhibits Transcription from Multiple Promoters and Activators

Abstract

The TATA binding protein (TBP) plays a central role in eukaryotic and archael transcription initiation. We describe the isolation of a novel 23-kDa human protein that displays 41% identity to TBP and is expressed in most human tissue. Recombinant TBP-related protein (TRP) displayed barely detectable binding to consensus TATA box sequences but bound with slightly higher affinities to nonconsensus TATA sequences. TRP did not substitute for TBP in transcription reactions in vitro. However, addition of TRP potently inhibited basal and activated transcription from multiple promoters in vitro and in vivo. General transcription factors TFIIA and TFIIB bound glutathione S-transferase-TRP in solution but failed to stimulate TRP binding to DNA. Preincubation of TRP with TFIIA inhibited TBP-TFIIA-DNA complex formation and addition of TFIIA overcame TRP-mediated transcription repression. TRP transcriptional repression activity was specifically reduced by mutations in TRP that disrupt the TFIIA binding surface but not by mutations that disrupt the TFIIB or DNA binding surface of TRP. These results suggest that TFIIA is a primary target of TRP transcription inhibition and that TRP may modulate transcription by a novel mechanism involving the partial mimicry of TBP functions.

TRF2: TRansForming the view of general transcription factors

“…59 TRF2 is the TRF protein with the least similarity to TBP. [60][61][62][63][64][65] In 1999-2000, when different research groups have cloned TRF2 from multiple species, different names were coined. The name TRF2 was used for Drosophila 64 and humans, 65 as it followed the discovery of TRF1 in Drosophila.…”

“…The name TRF2 was used for Drosophila 64 and humans, 65 as it followed the discovery of TRF1 in Drosophila. It was also named TLP (TATA-like protein; identified in mouse and humans), 62,63 TLF (TBP-like factor; identified in C. elegans), 60,66 TRP (TBP-related protein; identified in humans) 61 and TBPL1 (TBP-like 1; L is used by the Human Gene Nomenclature Committee to denote paralogs of named genes), based on its homology to TBP and perhaps, taking into account that there is no vertebrate TRF1. TRF2 is involved in RNAP II transcription.…”

“…65 Similarly to TRF1 and TRF3, TRF2 can directly interact with TFIIA 61,65,67 and TFIIB. 61 Interestingly, Drosophila trf2 encodes 2 protein products -a short (632 aa) protein, and a protein of 1715 aa (which will henceforth be referred to as long TRF2), in which the same short amino acid sequence is preceded by an N-terminal domain composed of coil-coiled motifs. 68 Translation of the short isoform probably results from an internal translation initiation by an IRES mechanism.…”

“…The long TRF2 has only been identified in Drosophila. The short TRF2, which is highly conserved in evolution, 45,55,61,64,69,70 has been extensively studied and will henceforth be referred to as TRF2. The TRF2 core domain shows 40% identity and 60% similarity to the TBP core domain.…”

TBP, un facteur de transcription universel ?

“…En effet, trois protéines TRF1 (TBP-related factor 1), TLF (TBP-like factor)/TRF2 et TRF3 ont été identifiées et caractérisées [11][12][13][14][15][16][17]. La similarité entre ces protéines est limitée au domaine carboxyterminal conservé (Figure 2A-C …”