Complex Interactions between Yeast TFIIIB and TFIIIC

Chaussivert, Nathalie; Conesa, Christine; Shaaban, Salam; Sentenac, André

doi:10.1074/jbc.270.25.15353

Cited by 84 publications

(143 citation statements)

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“…The favored model in the case of the PCF1-2 mutation (T167I in TPR2) involves a structural change within TFIIIC131 that affects the extent to which the binding reaction can proceed (25). Changes in the nature and/or accessibility of the TFIIIB70-binding site may also underlie the 4-fold decrease in the two-hybrid interaction that occurs when the minimal TFIIIB70 interaction domain, 131-1TPR-(1-165), is extended up to the end of TPR9 (15). The molecular and biochemical basis for these effects is not well understood at the present time and warrants further investigation.…”

mentioning

confidence: 88%

“…Based on the sequential pathway of binding established in yeast (14) together with other genetic and biochemical studies (discussed below), the TFIIIC⅐DNA complex is thought to interact initially with the TFIIB-related subunit of TFIIIB (Brf1p/TFIIIB70) via its tetratricopeptide repeat (TPR)-containing subunit, TFIIIC131 (15,16). Subsequently, protein-protein interactions between TFIIIB70 and TBP (16) facilitate the interaction of TBP with the DNA (17,18).…”

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confidence: 99%

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Interactions between the Tetratricopeptide Repeat-containing Transcription Factor TFIIIC131 and Its Ligand, TFIIIB70

Moir

Puglia

Willis

2000

Journal of Biological Chemistry

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In the transcription of tRNA and 5 S genes by RNA polymerase III, recruitment of the transcription factor (TF)IIIB is mediated by the promoter-bound assembly factor TFIIIC. A critical limiting step in this process is the interaction between the tetratricopeptide repeat (TPR)-containing subunit of TFIIIC (TFIIIC131) and the TFIIB-related factor Brf1p/TFIIIB70. To facilitate biochemical studies of this interaction, we expressed a fragment of TFIIIC131, TFIIIC131-(1-580), that includes the minimal TFIIIB70 interaction domain defined by two-hybrid studies together with adjacent sequences, up to the end of TPR9, implicated in the assembly reaction. TFIIIC131-(1-580) interacts with TFIIIB70 in solution and inhibits the formation of TFIIIB70⅐TFIIIC⅐DNA complexes. In a coupled equilibrium binding assay, the formation of TFIIIC131-(1-580)⅐TFIIIB70 complexes was adequately described by a single-site binding model and yielded an apparent equilibrium dissociation constant of 334 ؎ 23 nM. CD spectroscopy and limited proteolysis experiments defined a well structured and largely protease-resistant core in TFIIIC131-(1-580) comprising part of the hydrophilic amino terminus, TPR1-5, the intervening non-TPR region, and TPR6 -8. CD spectra showed that trifluoroethanol induced significant ␣-helical structure in TFIIIC131-(1-580). A more modest monovalent ion-dependent CD difference was observed in mixtures of TFIIIC131-(1-580) and TFIIIB70, suggesting that formation of the binary complex may proceed with the acquisition of ␣-helicity. Transcription factor (TF)1 IIIC is a large multisubunit complex that is responsible for recruiting the RNA polymerase III (pol III) initiation factor, TFIIIB, to the DNA upstream of the transcription start site of 5 S rRNA, tRNA, and related genes (1, 2). On tRNA and other genes containing A and B block promoter elements, the assembly reaction begins with nucleosome repositioning or displacement to enable high affinity binding of TFIIIC to the promoter (3-5). Interactions with the A block are thermodynamically weaker than those with the B block, and yet simultaneous binding to both sites occurs over a wide range of distances without regard to helical phasing (2). The conformational flexibility of TFIIIC indicated by these studies is also seen during the recruitment of TFIIIB. This is reflected by changes in site-specific photocross-linking of the 131-kDa subunit (TFIIIC131) (6) and by the ability of TFIIIC to co-direct (with the TATA-binding protein (TBP)) the placement of TFIIIB at different locations on the DNA (7).In addition to TFIIIB recruitment, recent studies have shown that TFIIIC has other functions and activities in pol III transcription. Subunits of TFIIIC in yeast (8) and humans (9, 10) have been shown to interact either genetically or biochemically with subunits of the polymerase that have been highly conserved through evolution. These studies suggest possible roles for TFIIIC in polymerase recruitment; pol III holoenzyme stabilization (11); and/or the cycle of elongation, termination, an...

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confidence: 88%

mentioning

confidence: 99%

Interactions between the Tetratricopeptide Repeat-containing Transcription Factor TFIIIC131 and Its Ligand, TFIIIB70

Moir

Puglia

Willis

2000

Journal of Biological Chemistry

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“…Given the complexity and incomplete purification of other general factors required by RNA Pol III, it is important to consider their potential relationships to TDF. The well-characterized human factors include TFIIIC2, which contains five subunits and binds to the B box, and a core TFIIIB, which contains TBP and a TFIIB-related polypeptide that, like its yeast homolog (Werner et al 1993;Chaussivert et al 1995), interacts both with a component of TFIIIC2 (Y. Hsieh, R. Kovelman, Z. Wang, and R.G. Roeder, unpubl.…”

Section: A Novel Accessory Factor For Initiation By Rna Pol IIImentioning

confidence: 99%

Identification of an autonomously initiating RNA polymerase III holoenzyme containing a novel factor that is selectively inactivated during protein synthesis inhibition

Wang

Luo²,

Roeder³

1997

Genes Dev.

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Eukaryotic RNA polymerases I, II, and III (Pol I, Pol II, Pol III) are structurally distinct, transcribe distinct sets of genes in conjunction with distinct sets of general initiation factors, and respond to largely distinct gene-specific activators (for review, see Zawel and Reinberg 1995;Roeder 1996a). Despite these differences, some mechanistic similarities are apparent. The three RNA polymerases share five common subunits and other subunits that are highly related (Woychik et al. 1990;McKune et al. 1995;Shpakovski et al. 1995), whereas the TATA-binding protein (TBP) is shared by three RNA polymerase type-specific accessory factors (Struhl 1994). Studies with isolated components have shown ordered pathways for the assembly of RNA polymerases and cognate initiation factors into active preinitiation complexes (for review, see Zawel and Reinberg 1995;Roeder 1996a). In addition, there is a parallel between RNA Pol II recruitment by interaction with the TFIIB component of a TFIIB-TFIID-promoter complex (for review, see Roeder 1996b) and RNA Pol III recruitment by interaction with a TFIIB-related component of a TFIIIB-TFIIIC-promoter complex (Werner et al. 1993; Wang and Roeder 1997).Although the stepwise assembly of functional preinitiation complexes is readily demonstrated in vitro, recent studies have identified large complexes (RNA Pol II ''holoenzymes'') that contain RNA Pol II, some or all of the general initiation factors, and various cofactors (Kim et al.

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“…Some evidence places it near the carboxyl-terminal stirrup of TBP (20, 21). The amino-terminal domain of Brf1 interacts with the 131 subunit of TFIIIC as well as the C34 subunit of pol III (14,22). This domain also plays an important role in open complex formation (23,24), the stage at which the template and transcribed strands are separated in preparation for transcription initiation.…”

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confidence: 99%

“…However, most pol III genes with an internal promoter lack a TATA box. TBP is delivered to the upstream region of these promoters by Brf1, and Brf1 is recruited by TFIIIC (13)(14)(15).…”

mentioning

confidence: 99%

Inhibition of TATA Binding Protein Dimerization by RNA Polymerase III Transcription Initiation Factor Brf1

Alexander¹,

Kaczorowski²,

Jackson-Fisher³

et al. 2004

Journal of Biological Chemistry

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The Brf1 subunit of TFIIIB plays an important role in recruiting the TATA-binding protein (TBP) to the upstream region of genes transcribed by RNA polymerase III. When TBP is not bound to promoters, it sequesters its DNA binding domain through dimerization. Promoter assembly factors therefore might be required to dissociate TBP into productively binding monomers. Here we show that Saccharomyces cerevisiae Brf1 induces TBP dimers to dissociate. The high affinity TBP binding domain of Brf1 is not sufficient to promote TBP dimer dissociation but in addition requires the TFIIB homology domain of Brf1. A model is proposed to explain how two distinct functional domains of Brf1 work in concert to dissociate TBP into monomers.Eukaryotic genes are transcribed by one of three RNA polymerases, pol 1 I, II, or III. In higher eukaryotes, there are two main pathways of assembling a pol III transcription complex, which are governed in large part by distinct promoter elements located either upstream or downstream of the transcriptional start site (1-3). In the budding yeast Saccharomyces cerevisiae, one major assembly pathway exists, and it involves the binding of TFIIIC to promoter elements internal to tRNA genes. TFIIIC then recruits TFIIIB to a location immediately upstream of the transcriptional start site (4, 5). TFIIIB then directs pol III to the transcriptional start site. TFIIIB is composed of three subunits: the TATA binding protein (TBP), Brf1, and Bdp1 (6 -10).TBP is important for the expression of essentially all eukaryotic genes. It is a saddle shaped protein having aminoand carboxyl-terminal stirrups and a concave/convex surface (11,12). TBP binds to a TATA box promoter element when it is present. However, most pol III genes with an internal promoter lack a TATA box. TBP is delivered to the upstream region of these promoters by Brf1, and Brf1 is recruited by TFIIIC (13-15).The amino-terminal half of Brf1 is homologous to the pol II general transcription factor TFIIB (16 -18). TFIIB binds to TBP along its carboxyl-terminal stirrup, pinning it to DNA (19). In contrast to TFIIB, the TFIIB homology domain of Brf1 has not been shown to independently bind TBP. Where or whether it interacts with TBP is largely unknown. Some evidence places it near the carboxyl-terminal stirrup of TBP (20, 21). The amino-terminal domain of Brf1 interacts with the 131 subunit of TFIIIC as well as the C34 subunit of pol III (14,22). This domain also plays an important role in open complex formation (23,24), the stage at which the template and transcribed strands are separated in preparation for transcription initiation. The carboxyl-terminal half of Brf1 is unrelated to TFIIB but is conserved among Brf proteins. A portion of the carboxyl-terminal half (437-506) of Brf1 binds with high affinity to the convex surface of TBP, snaking along the "top" of TBP and down its amino-terminal stirrup (25).TBP self-associates into dimers and possibly higher order structures through its concave DNA binding surface and carboxyl-terminal stirrup (26 -39). ...

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Complex Interactions between Yeast TFIIIB and TFIIIC

Cited by 84 publications

References 32 publications

Interactions between the Tetratricopeptide Repeat-containing Transcription Factor TFIIIC131 and Its Ligand, TFIIIB70

Interactions between the Tetratricopeptide Repeat-containing Transcription Factor TFIIIC131 and Its Ligand, TFIIIB70

Identification of an autonomously initiating RNA polymerase III holoenzyme containing a novel factor that is selectively inactivated during protein synthesis inhibition

Inhibition of TATA Binding Protein Dimerization by RNA Polymerase III Transcription Initiation Factor Brf1

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