Distinct TFIID complexes mediate the effect of different transcriptional activators.

Brou, Christel; Chaudhary, Sunita; Davidson, Irwin; Lutz, Yves; Jun, Wu; Egly, Jean Marc; Tora, Làszlò; Chambon, Pierre

doi:10.1002/j.1460-2075.1993.tb05681.x

Cited by 181 publications

(179 citation statements)

References 91 publications

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“…pol I, TIF-IA, and TIF-IC were purified as described (4, 16). TIF-IB was immunopurified using mAb 3G3 (11,15). FLAG-tagged UBF was immunopurified from extracts of baculovirus-infected Sf9 cells.…”

Section: Methodsmentioning

confidence: 99%

Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1

Heix

Zomerdijk

Ravanpay

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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Promoter selectivity for all three classes of eukaryotic RNA polymerases is brought about by multimeric protein complexes containing TATA box binding protein (TBP) and specific TBP-associated factors (TAFs). Unlike class II-and III-specific TBP-TAF complexes, the corresponding murine and human class I-specific transcription initiation factor TIF-IB͞ SL1 exhibits a pronounced selectivity for its homologous promoter. As a first step toward understanding the molecular basis of species-specific promoter recognition, we cloned the cDNAs encoding the three mouse pol I-specific TBP-associated factors (TAF I s) and compared the amino acid sequences of the murine TAF I s with their human counterparts. The four subunits from either species can form stable chimeric complexes that contain stoichiometric amounts of TBP and TAF I s, demonstrating that differences in the primary structure of human and mouse TAF I s do not dramatically alter the network of protein-protein contacts responsible for assembly of the multimeric complex. Thus, primate vs. rodent promoter selectivity mediated by the TBP-TAF I complex is likely to be the result of cumulative subtle differences between individual subunits that lead to speciesspecific properties of RNA polymerase I transcription.Transcription initiation by all three classes of eukaryotic nuclear RNA polymerases is a complex process, requiring concerted interactions between multiple protein factors and RNA polymerase. Each class of RNA polymerase uses a distinct assortment of transcription factors that are thought to nucleate the assembly of transcription initiation complexes at specific promoters. For transcription governed by RNA polymerase I (pol I), the murine transcription initiation factor (TIF) IB and its human homologue SL1 have been shown to direct the assembly of productive initiation complexes at the mouse and human rDNA promoter (1-3). TIF-IB͞SL1 is thought to communicate with the upstream binding factor (UBF) and to recruit pol I together with the associated factors TIF-IA and TIF-IC to the template (4).Earlier studies had revealed that rDNA transcription is speciesspecific, requiring factors from either the same or very closely related species (5). Most of the factors, i.e., UBF, pol I, TIF-IA, and TIF-IC, are interchangeable between human and mouse (3, 6-9) whereas TIF-IB͞SL1 has been found to be the speciesspecific component in the preinitiation complex (3, 9). A significant advance toward a functional characterization of this selectivity factor was the discovery that TIF-IB͞SL1 is a multiprotein complex consisting of TATA box binding protein (TBP) and three TBP-associated factors (TAFs) (10, 11). Given the low abundance of TIF-IB͞SL1 in the cell, studies on the molecular mechanism of promoter recognition and species-specific transcription require the isolation and functional characterization of the individual subunits of TIF-IB and SL1. Recently, this was accomplished for the components of SL1 (12, 13). Here we report the cloning and expression of the cDNAs encodi...

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Section: Methodsmentioning

confidence: 99%

Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1

Heix

Zomerdijk

Ravanpay

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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“…An important question was whether this also reflected the composition of TFIID: is TFIID disrupted by TAF9 depletion, or does it stay relatively intact such that only the levels of free TAFs are reduced? To distinguish between these possibilities, coimmunoprecipitation (co-IP) experiments using an anti-TBP mAb (35) were performed with extracts from DT40-TAF9 cells grown in the presence of tet (1 g/ml) for 0, 36, and 72 h, and precipitates were analyzed by Western blotting (Fig. 1).…”

Section: Taf9 Depletionmentioning

confidence: 99%

In Vivo Functional Analysis of the Histone 3-like TAF9 and a TAF9-related Factor, TAF9L

Chen¹,

Manley

2003

Journal of Biological Chemistry

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The majority of the TATA-binding protein (TBP)-associated factors (TAFs) that constitute transcription factor II D (TFIID) contain histone fold motifs (HFMs). Our previous results utilizing DT40 cells containing a conditional TAF9 allele indicated that the histone 3-like TAF9 is essential for cell viability but largely dispensable for general transcription. In this study, we investigated further the role of TAF9 structural domains in TFIID integrity and cell growth and the functions of a TAF9-related factor, TAF9L. We first show that TAF9 depletion severely disrupts TFIID, indicating that the observed ongoing transcription is initiated with at least partially TAF-free TATA-binding protein. We also provide evidence for specific roles of TAF HFMs, highlighting the functional significance of HFM specificity observed in vitro and, importantly, of the TAF9-histone 3 similarity. Although we provide evidence that TAF9 and TAF9L are partly redundant, RNA interference experiments suggest that TAF9L is essential for HeLa cell growth. Strikingly, we provide evidence that TAF9L plays a role in transcriptional repression and/or silencing.Initiation of transcription mediated by RNA polymerase II (RNAP II) 1 requires a number of general transcription factors (GTFs), among which TFIID is the major core promoter recognition factor. TFIID is composed of highly conserved subunits, including the TATA-binding protein (TBP) and about 12-14 TBP-associated factors (TAFs) (1-4). Despite their diverse sequence and structural features, most TAFs (9 of 14 in yeast) contain domains known as histone fold motifs (HFMs) that display varying degrees of similarity with canonical histone core domains (5). TAF HFMs have been shown to mediate highly specific pairwise TAF-TAF interactions in cocrystal structures, in vitro interaction assays, and coexpression analyses (5-9). Furthermore, histone-like TAFs were shown in immunolabeling/electron microscopy analysis to colocalize to specific TFIID subdomains (10, 11) in a pattern consistent with the above pairwise TAF interactions (12). Additionally, four yeast histone-like TAFs, TAF6/9 (H4/H3-like) and TAF4/12 (H2A/ H2B-like), were reconstituted into a histone octamer-like complex in vitro (13). However, the roles of the HFMs in TFIID structure and function in vivo are still unclear for most TAFs, especially in vertebrates. For example, the highly conserved arginine residues in histones that contact DNA are missing in TAFs (14), suggesting that histones and histone-like TAFs contact DNA differently.A subset of the histone-like TAFs were also found to be integral components of histone acetyltransferase (HAT) protein complexes, including SAGA in yeast and GCN5, PCAF, TFTC, and STAGA in vertebrates (2, 3, 15, 16). These HAT complexes are larger than TFIID, containing GCN5 or PCAF HAT activity and other factors likely involved in diverse nuclear processes (17, 18). Importantly, however, histone-like TAFs that are missing in the vertebrate HAT complexes are replaced with a different set of HFM-containing sub...

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“…MAbs against hTAF II 28 (15TA and 1C9), TBP (3G3), and the B10 epitope of the ER were as previously described (1,5,18,25).…”

Section: Transfection Of Cos Cells and Immunoprecipitationsmentioning

confidence: 99%

Synergistic Transcriptional Activation by TATA-Binding Protein and hTAF_II28 Requires Specific Amino Acids of the hTAF_II28 Histone Fold

Lavigne

Gangloff

et al. 1999

Molecular and Cellular Biology

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Coexpression of the human TATA-binding protein (TBP)-associated factor 28 (hTAF II 28) with the alteredspecificity mutant TBP spm3 synergistically enhances transcriptional activation by the activation function 2 of the nuclear receptors (NRs) for estrogen and vitamin D 3 from a reporter plasmid containing a TGTA element in mammalian cells. This synergy is abolished by mutation of specific amino acids in the ␣2-helix of the histone fold in the conserved C-terminal region of hTAF II 28. Critical amino acids are found on both the exposed hydrophilic face of this helix and the hydrophobic interface with TAF II 18. This ␣-helix of hTAF II 28 therefore mediates multiple interactions required for coactivator activity. We further show that mutation of specific residues in the H1 ␣-helix of TBP either reduces or increases interactions with hTAF II 28. The mutations which reduce interactions with hTAF II 28 do not affect functional synergy, whereas the TBP mutation which increases interaction with hTAF II 28 is defective in its ability to synergistically enhance activation by NRs. However, this TBP mutant supports activation by other activators and is thus specifically defective for its ability to synergize with hTAF II 28.The RNA polymerase II transcription factor TFIID is a multiprotein complex composed of the TATA-binding protein (TBP) and a series of TBP-associated factors (TAF II s) (3, 7). Not only are TAF II s components of transcription factor TFIID, but distinct subsets of TAF II s are also components of the SAGA, PCAF, and TFTC complexes (13,14,21,31,40). For human TFIID (hTFIID), cDNAs for 11 hTAF II s have been characterized (10,16,18,24,25).Genetic and biochemical experiments show that some TAF II s are important for promoter recognition and expression of a subset of promoters (15,38,39), while others are more generally required for transcription in Saccharomyces cerevisiae (2,26,27,29 Expression of hTAF II 28 also potentiates ligand-dependent activation by the AF-2s of many NRs, the most dramatic effects being seen with the receptors for 9-cis retinoic acid (retinoid X receptor), estrogen (estrogen receptor [ER]), and the VDR (22). Deletion analysis showed that coactivator activity required amino acids 150 to 179 in the C-terminal domain of hTAF II 28. Subsequent determination of the three-dimensional structure of the hTAF II 28/hTAF II 18 heterodimer at 2.6-Å resolution by X-ray crystallography indicated that these two proteins interact via a histone fold motif present in the C-terminal domain of hTAF II 28 and in the central region of hTAF II 18 (4). Amino acids 150 to 179 required for coactivator activity form the amphipathic ␣2-helix of the hTAF II 28 histone fold. In the hTAF II 28/hTAF II 18 heterodimer, residues on the hydrophobic face of the ␣2-helix make intermolecular contacts with hTAF II 18, while the residues on the mainly hydrophilic solvent-exposed face are available for mediating interactions with other proteins.Although the ability of hTAF II 28 to act as a transcriptional coactivator did no...

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Distinct TFIID complexes mediate the effect of different transcriptional activators.

Cited by 181 publications

References 91 publications

Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1

Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1

In Vivo Functional Analysis of the Histone 3-like TAF9 and a TAF9-related Factor, TAF9L

Synergistic Transcriptional Activation by TATA-Binding Protein and hTAF_II28 Requires Specific Amino Acids of the hTAF_II28 Histone Fold

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Distinct TFIID complexes mediate the effect of different transcriptional activators.

Cited by 181 publications

References 91 publications

Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1

Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1

In Vivo Functional Analysis of the Histone 3-like TAF9 and a TAF9-related Factor, TAF9L

Synergistic Transcriptional Activation by TATA-Binding Protein and hTAFII28 Requires Specific Amino Acids of the hTAFII28 Histone Fold

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Synergistic Transcriptional Activation by TATA-Binding Protein and hTAF_II28 Requires Specific Amino Acids of the hTAF_II28 Histone Fold