DA-Complex Assembly Activity Required for VP16C Transcriptional Activation

Kobayashi, N.; Horn, Peter J.; Sullivan, Susan M.; Triezenberg, Steven J.; Boyer, Thomas G.; Berk, Arnold

doi:10.1128/mcb.18.7.4023

Cited by 42 publications

(42 citation statements)

References 61 publications

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“…Given that the VP16 activation domain and TAND-1 have similar TBP-binding characteristics (20), we considered the possibility that the VP16 activation domain forms a stoichiometric complex with TBP when fused to TAND-2. Consistent with previous reports (27)(28)(29), the VP16 activation domain (residues 457ϳ490 or 470ϳ490) per se interacts very weakly with TBP. Although TBP bound to glutathione S-transferase-VP16 (GST-VP16) can be detected by immunoblotting (Fig.…”

Section: Resultssupporting

confidence: 81%

“…Next, we tested whether a VP16 mutant (F475S, M478T, F479S), which has no potential as an activation domain (29), can function as yTAND-1 when integrated into the TFIID complex. This triple point mutation within the VP16 segment (residues 470ϳ490) completely abolishes both transcription ability (data not shown) and interaction activity with TBP (Fig.…”

Section: Acidic Activation Domains Can Function As Tand-1 When Integrmentioning

confidence: 99%

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A role of transcriptional activators as antirepressors for the autoinhibitory activity of TATA box binding of transcription factor IID

Kotani

Banno

Ikura

et al. 2000

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

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. 2). An alternative model postulates that the holoenzyme enters the preinitiation complex as a preassembled unit (2, 3). Although the nature of the assembly pathway most relevant to the in vivo context remains unclear, access of TFIID to the core promoter is likely to be a critical step in any pathway, given that only TFIID binds to the promoter in a sequence-specific manner. In support of this view, in vitro recruitment experiments using immobilized promoters demonstrated that the holoenzyme is not recruited independently of TFIID and TFIIA (4).TFIID is a multimeric protein complex consisting of the TATA box-binding protein (TBP) and Ͼ10 distinct TBPassociated factors (TAFs), which are conserved from yeast to man (reviewed in ref. . Consistent with these observations in vivo, TAF-independent activation was demonstrated in transcriptional experiments in vitro, using TFIID-depleted HeLa nuclear extracts, which could possess activator targets other than TAFs (8), or even with a highly purified cell-free transcription system (9, 10). Furthermore, transcription activation is reconstituted by supplementing purified yeast holoenzyme with only TBP (11, 12). These observations suggest that activators contribute to activated transcription by interacting with multiple targets (e.g., basal factors, TAFs, SRB mediators, or other unknown cofactors).Although TAFs are well recognized as positive cofactors, in our view, at least certain TAFs are negative cofactors. Importantly, highly purified TFIID manifests lower transcriptional activity than TBP alone (13) and binds to the core promoter poorly (reviewed in ref. 14). This inhibitory activity for promoter binding in TFIID is suppressed by limited proteolysis of TFIID or by TFIIA (14,15). These results strongly suggest that this inhibitory activity could be intrinsic to TFIID and derived from TAF(s) and is sensitive to proteases. Consistent with this idea, Drosophila (d)TAF230, or the homologous yTAF145, inhibits TBP binding to the TATA box when these TAFs are mixed with TBP in vitro (16)(17)(18). Mutational analyses of dTAF230 indicate that the N-terminal 156 residues inhibit TATA box binding through direct interaction with TBP (19,20). This N-terminal domain (designated as TAND; TAF N-terminal domain), has been dissected into subdomain 1 (dTAND-1; residues 11-77) and subdomain 2 (dTAND-2; residues 82-156), which bind to the concave undersurface and the convex upper surface of TBP in This paper was submitted directly (Track II) to the PNAS office.

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Section: Resultssupporting

confidence: 81%

Section: Acidic Activation Domains Can Function As Tand-1 When Integrmentioning

confidence: 99%

A role of transcriptional activators as antirepressors for the autoinhibitory activity of TATA box binding of transcription factor IID

Kotani

Banno

Ikura

et al. 2000

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

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“…This indicates that basic mechanisms of transcription activation are conserved amongst eukaryotes. The VP16 TAD targets basal Pol II transcription factors, including TFIIA, TFIIB, TFIID, the TFIIH subunit Tfb1/p62 (yeast/human) and the Mediator co-activator [18][19][20][21][22][23] . The VP16 TAD binds the Mediator subunit Med25 (also called Arc92) [24][25][26][27] , which is specific to higher eukaryotes.…”

mentioning

confidence: 99%

Structure and VP16 binding of the Mediator Med25 activator interaction domain

Vojnic

Mourão

Seizl

et al. 2011

Nat Struct Mol Biol

113

161

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4 0 4 VOLUME 18 NUMBER 4 APRIL 2011 nAture structurAl & moleculAr biologyActivator proteins regulate eukaryotic RNA polymerase II (Pol II) transcription in response to developmental and environmental signals. They bind to the DNA recognition sites of target genes with a sequence-specific DNA-binding domain, and recruit components of the Pol II machinery through a transcriptional activation domain (TAD) 1,2 . Activators have been classified as acidic, glutamine-rich, proline-rich and serine/threonine-rich, depending on the preponderance of amino acids in their TAD 3 . An archetypal acidic activator is the herpes simplex virus protein 16 (VP16), which activates the expression of immediate early viral genes during infection 4-8 . VP16 exerts its activating function through a C-terminal TAD that includes residues 413-490 (refs. 9-13). The VP16 TAD has been intensely used for studying transcriptional activation. Usually, the VP16 TAD is fused with its N terminus to the DNA-binding domain of the yeast transcription factor Gal4. The resulting Gal4-VP16 activator fusion protein stimulates transcription from promoters that contain Gal4-binding sites in the yeast and mammalian transcription systems in vivo 14,15 and in vitro 16,17 . This indicates that basic mechanisms of transcription activation are conserved amongst eukaryotes. The VP16 TAD targets basal Pol II transcription factors, including TFIIA, TFIIB, TFIID, the TFIIH subunit Tfb1/p62 (yeast/human) and the Mediator co-activator [18][19][20][21][22][23] . The VP16 TAD binds the Mediator subunit Med25 (also called Arc92) [24][25][26][27] , which is specific to higher eukaryotes. Med25 consists of two domains, the activator interaction domain (ACID) 24 that binds the VP16 TAD, and a 'von Willebrand factor type A' domain that anchors Med25 to Mediator 24 . Mediator generally conveys regulatory information by forming a bridge between activators and the basal Pol II machinery 28,29 . Whereas information on the core Mediator structure is emerging, structural information about its more peripheral activator-binding domains is limited to the KIX domain in subunit Med15 (or Arc105) 30,31 .The VP16 TAD is intrinsically flexible, whereas the VP16 core domain (residues 49-402) forms a stable structure 23,[32][33][34] . The TAD contains two functional subdomains, H1 (residues 410-452) and H2 (residues 453-490), which activate transcription independently 35,36 . Both H1 and H2 contain acidic amino acids, but specific bulky hydrophobic and aromatic residues are required for their function [36][37][38][39] . H2 has been proposed to adopt an α-helical conformation when bound to TFIIB 40 . NMR analysis revealed a nine-residue amphipathic α-helix in H2 that docks onto a PH fold in Tfb1 21 . On the basis of these and other results it is assumed that acidic TADs are flexible in their free state, but become transiently structured upon interaction with their target proteins.Here we report the NMR structure of the Mediator Med25 ACID and analyze its structural and functional interaction wi...

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“…Finally, TFIIA can compete with negative factors such as NC2, Mot1, and the Taf1 TAND domain for binding to TBP (Hampsey 1998;Kokubo et al 1998;Ozer et al 1998b;Cang et al 1999). TFIIA has also been found to interact with at least two Tafs and some transcription activators, using two-hybrid and affinity chromatography analysis (Yokomori et al 1993;Ozer et al 1994;Kobayashi et al 1998;Kraemer et al 2001).…”

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confidence: 99%

Positive and negative functions of the SAGA complex mediated through interaction of Spt8 with TBP and the N-terminal domain of TFIIA

Warfield

Ranish²,

Hahn³

2004

Genes Dev.

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A surface that is required for rapid formation of preinitiation complexes (PICs) was identified on the N-terminal domain (NTD) of the RNA Pol II general transcription factor TFIIA. Site-specific photocross-linkers and tethered protein cleavage reagents positioned on the NTD of TFIIA and assembled in PICs identified the SAGA subunit Spt8 and the TFIID subunit Taf4 as located near this surface. In agreement with these findings, mutations in Spt8 and the TFIIA NTD interact genetically. Using purified proteins, it was found that TFIIA and Spt8 do not stably bind to each other, but rather both compete for binding to TBP. Consistent with this competition, Spt8 inhibits the binding of SAGA to PICs in the absence of activator. In the presence of activator, Spt8 enhances transcription in vitro, and the positive function of the TFIIA NTD is largely mediated through Spt8. Our results suggest a mechanism for the previously observed positive and negative effects of Spt8 on transcription observed in vivo.[Keywords: Transcription; SAGA; TFIIA; coactivator; repression] Supplemental material is available at http://www.genesdev.org.

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DA-Complex Assembly Activity Required for VP16C Transcriptional Activation

Cited by 42 publications

References 61 publications

A role of transcriptional activators as antirepressors for the autoinhibitory activity of TATA box binding of transcription factor IID

A role of transcriptional activators as antirepressors for the autoinhibitory activity of TATA box binding of transcription factor IID

Structure and VP16 binding of the Mediator Med25 activator interaction domain

Positive and negative functions of the SAGA complex mediated through interaction of Spt8 with TBP and the N-terminal domain of TFIIA

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