The TBP-TFIIA Interaction in the Response to Acidic Activators in Vivo

Stargell, Laurie A.; Struhl, Kevin

doi:10.1126/science.7604282

Cited by 106 publications

(124 citation statements)

References 46 publications

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“…(iv) Mutations affecting the surface of TBP that interacts with TFIIA reduce TFIIA binding in vitro and also interfere with transcriptional activation in vivo (6,41). (v) As reported here, a correlation exists between DA-complex assembly activity and in vivo activation function for mutants of VP16C.…”

Section: (Iii) Formentioning

confidence: 78%

“…These results suggest that TFIIB binding is not a limiting step in transcription, as might be expected for a regulated step. In contrast, mutations in TBP residues in the interface between TBP and TFIIA that reduce the affinity of TFIIA for the TBP-TATA box complex severely reduce the ability of TBP to participate in activated transcription in vivo but do not impair basal transcription (6,41).…”

Section: (Iii) Formentioning

confidence: 99%

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DA-Complex Assembly Activity Required for VP16C Transcriptional Activation

Kobayashi

Horn

Sullivan

et al. 1998

Molecular and Cellular Biology

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One class of transcriptional activation domains stimulates the concerted binding of TFIIA and TFIID to promoter DNA. To test whether this DA-complex assembly activity contributes significantly to the overall mechanism of activation in vivo, we analyzed mutants of the 38-amino-acid residue VP16C activation subdomain from herpes simplex virus. An excellent correlation was observed between the in vivo activation function of these mutants and their in vitro DA-complex assembly activity. Mutants severely defective for in vivo activation also showed reduced in vitro binding to native TFIIA. No significant correlation between in vivo activation function and in vitro binding to human TATA binding protein, human TFIIB, or Drosophila melanogaster TAF II 40 was observed for this set of VP16C mutants. These results argue that the ability of VP16C to increase the rate and extent of DA-complex assembly makes a significant contribution to the overall mechanism of transcriptional activation in vivo.Considerable experimental evidence indicates that transcriptional activators bound to enhancer and promoter proximal sequences stimulate transcription through interactions between their activation domains and components of the initiation complex assembled at the associated promoter (33,36,39,42,46). These interactions have been postulated to stimulate the assembly of initiation complexes at promoters or to affect the activities of general transcription factors in the assembled initiation complex so as to increase the rate of initiation by polymerase II (Pol II). But with few exceptions, relatively little is understood about the detailed mechanism by which specific activators stimulate transcription.Some activation domains have been found to increase both the rate and the final extent of an early step in initiation complex assembly, the concerted binding of TFIIA and TFIID to the TATA box and initiation site region of the promoter (8,9,24,28,49). This DA-complex assembly activity can be conveniently assayed in vitro by an electrophoretic mobility shift assay (EMSA) using agarose gels to separate the large DNAprotein complexes involved (28). Activators that stimulate DA-complex assembly also interact directly with TFIIA, as observed by coimmunoprecipitation and affinity column chromatography with recombinant proteins (24,32).An extensive mutational analysis of a well-studied activation domain with DA-complex assembly activity, the 38-residue Cterminal activation subdomain of herpes simplex virus type 1 VP16, called VP16C, has recently been completed (43a). A number of single-, double-, and triple-point mutants of this sequence with various levels of activation function in vivo in Saccharomyces cerevisiae were identified. Since wild-type (wt) VP16C exhibits DA-complex assembly activity (24), the isolation of these VP16C mutants allowed us to test whether this in vitro activity correlated with their in vivo activation function, as would be expected if DA-complex assembly contributes significantly to the overall mechanism of activation in...

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Section: (Iii) Formentioning

confidence: 78%

Section: (Iii) Formentioning

confidence: 99%

DA-Complex Assembly Activity Required for VP16C Transcriptional Activation

Kobayashi

Horn

Sullivan

et al. 1998

Molecular and Cellular Biology

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“…The high local concentration afforded by this tether and its flexibility should diminish the sensitivity of Brf1c⅐Bdp1 binding to adventitious effects of mutations on Brf1c⅐TBPc binding. A similar approach was used to rescue the TFIIA binding defect of a TBP mutant protein in yeast (18). The ability of TBPc-Brf1c to assemble Bdp1 onto DNA and to function for transcription has been documented (8) and is further analyzed below.…”

Section: Resultsmentioning

confidence: 99%

Mapping the Principal Interaction Site of the Brf1 and Bdp1 Subunits of Saccharomyces cerevisiae TFIIIB

Kassavetis

Driscoll²,

Geiduschek

2006

Journal of Biological Chemistry

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The Brf1 subunit of the central RNA polymerase (pol) III transcription initiation factor TFIIIB is bipartite; its N-terminal TFIIBrelated half is principally responsible for recruiting pol III to the promoter and for promoter opening near the transcriptional start site, whereas its pol III-specific C-terminal half contributes most of the affinities that hold the three subunits of TFIIIB together. Here, the principal attachment site of Brf1 for the Bdp1 subunit of TFIIIB has been mapped by a combination of structure-informed, site-directed mutagenesis and photochemical protein-DNA cross-linking. A 66-amino acid segment of Brf1 is shown to serve as a two-sided adhesive surface, with the side chains projecting away from its extended interface with TATA-binding protein anchoring Bdp1 binding. An extensive collection of N-terminal, C-terminal, and internal deletion proteins has been used to demarcate the interacting Bdp1 domain to a 66-amino acid segment that includes the SANT domain of this subunit and is phylogenetically the most conserved region of Bdp1.The RNA polymerase (pol) 3 III transcription apparatus of yeast comprises, in addition to the polymerase itself, three transcription initiation factors, TFIIIA, -B, and -C.The three-subunit TFIIIB is the core initiation factor required and sufficient for recruiting pol III to the promoter and accurately initiating transcription. The large six-subunit TFIIIC places TFIIIB on DNA upstream of the transcriptional start site and protects the generally very small pol III transcription units from encroachment by repressive chromatin (1, 2). TFIIIA is the 5 S rRNA gene-specific factor that places TFIIIC on the transcription unit-internal promoter of these genes (reviewed in Refs. 3-5).The work that is presented here deals with the structure of TFIIIB, which is composed of three subunits: the TATA-binding protein (TBP), Brf1, and Bdp1. TBP and Brf1 bind tightly and co-purify, whereas Bdp1 dissociates during later steps of conventional column chromatography. (The two separated fractions of TFIIIB have been designated BЈ and BЉ, and B double prime has been adopted as the eponym of the Bdp1 subunit.) The 596-amino acid Brf1 is a fusion protein, with an N-terminal half that is related to the pol II transcription initiation factor TFIIB and a pol III-specific C-terminal half. A conserved segment of the C-terminal half (homology domain II; amino acids 439 -515) constitutes the Brf1 high affinity binding site for the evolutionarily highly conserved core of TBP (comprising all but the N-terminal 60 amino acids of the Saccharomyces cerevisiae protein); the N-terminal half of Brf1 engages TBP through a separate lower affinity interaction.The N-and C-terminal halves of Brf1 also provide separate Bdp1-docking sites, with the C-proximal homology domain II contributing the higher Bdp1 affinity. TBP makes only a minor direct contribution to bringing Bdp1 into TFIIIB. Thus, the pol III-specific half of Brf1 appears to contribute the interactions that principally hold TFIIIB together. Ind...

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“…Results of crystallographic and mutant analyses of TBP revealed that Ala-184/Leu-185 (86/87), Asn-189 (91), and Arg-205 (107) in the ␣-helix 1, ␤-sheet 2, and COOH terminus adjacent to the ␤-sheet 3 region of the tandem repeat of human TBP (yeast TBP) made contact with amino acids of TOA2 and were required for TFIIA binding (6,52,53). Basic amino acids in the ␣-helix 2 region have been proposed to be involved in TBP-DNA-TFIIA complex formation (55,56). Mutation of basic amino acids at Arg-231 and Arg-239 in this region of human TBP diminished the binding ability to the TFIIA column (6).…”

Section: Discussionmentioning

confidence: 99%

Specific Interaction with Transcription Factor IIA and Localization of the Mammalian TATA-binding Protein-like Protein (TLP/TRF2/TLF)

Nakadai

Shimada

Shima

et al. 2004

Journal of Biological Chemistry

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TBP-like protein (TLP) is structurally similar to the TATA-binding protein (TBP) and is thought to have a transcriptional regulation function. Although TLP has been found to form a complex with transcription factor IIA (TFIIA), the in vivo functions of TFIIA for TLP are not clear. In this study, we analyzed the interaction between TLP and TFIIA. We determined the biophysical properties for the interaction of TLP with TFIIA. Dissociation constants of TFIIA versus TLP and TFIIA versus TBP were 1.5 and 10 nM, respectively. Moreover, the dissociation rate constant of TLP and TFIIA (1. (1) and is thought to be a unique universal transcription factor (2). In the case of RNA polymerase II genes, TBP binds to the TATA-box element found in genes transcribed by RNA polymerase II and then triggers the preinitiation complex assembly (3). TBP directly binds to the general transcription factor IIA (TFIIA). TFIIA facilitates binding of TBP to DNA via several distinct mechanisms and thus activates TBP-dependent transcription of class II genes. TFIIA promotes stabilization of TBP on the TATA box by inducing a conformational change of TBP (4, 5). Furthermore, TFIIA acts as an anti-repressor against co-repressors that inhibit DNA binding and TFIIB binding of TBP (6, 7). TBP or TFIID forms a transcription-inactive homodimer in solution, and dissociation of a TBP dimer is induced by direct interaction of TFIIA (8,9,11,12). Those processes concerning TFIIA functions are further influenced by distinct classes of TFIIA-interactive regulatory factors. Because some transcriptional activations are dependent on TFIIA/TBP and TFIIA/activator interactions (6, 13-20), TFIIA is thought to be responsible for promoter selectivity for the RNA polymerase II transcription machinery via interactions with both regulatory factors and TBP.Higher eukaryotes have TBP family genes. A TBP-related factor involved in neurogenesis, TBP-related factor 1 (TRF1), has been identified in Drosophila (21). TRF1 forms a multiprotein complex with novel proteins (22), binds to promoter DNA bearing a non-traditional TATA box, and directs embryogenesis-related expression of the tudor gene (23). A recent study has also demonstrated that TRF1 rather than TBP formed a complex with TAFs of TFIIIB and directs the expression of class III genes (24). Thus, TRF1 is thought to behave as a promoterselective factor like bacterial factors (25), although it is still a mystery why TRF1 has been identified only in Drosophila.At least one other TBP-like protein (TLP) exists in metazoa (26 -28). It has been shown that defects in functional TLP in several animals resulted in developmental abnormalities accompanying decreased expression levels of particular genes (29 -34). Recently, we reported that a promoter-bound TLP and free TLP functioned as transcriptional activators (35,36) and that TLP affected levels of transcription of some cell cyclerelated genes in chicken cells (37). The PCNA gene was identified as a native target of TRF2/TLP in Drosophila (38). These findings suggest that TL...

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The TBP-TFIIA Interaction in the Response to Acidic Activators in Vivo

Cited by 106 publications

References 46 publications

DA-Complex Assembly Activity Required for VP16C Transcriptional Activation

DA-Complex Assembly Activity Required for VP16C Transcriptional Activation

Mapping the Principal Interaction Site of the Brf1 and Bdp1 Subunits of Saccharomyces cerevisiae TFIIIB

Specific Interaction with Transcription Factor IIA and Localization of the Mammalian TATA-binding Protein-like Protein (TLP/TRF2/TLF)

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