Eukaryotic activators function during multiple steps of preinitiation complex assembly

Choy, Bob K.; Green, Michael R.

doi:10.1038/366531a0

Cited by 285 publications

(283 citation statements)

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“…While TAF40 has been shown to contact the VP16 activation domain (15), this contact is to the C-terminal 452-to-490 sequence and not to the more N-terminal 412-to-456 sequence that, when multimerized, is fully sufficient to activate transcription efficiently (11,41). While TFIIB has been clearly implicated as a target for VP16, evidence also indicates that VP16 can affect initiation complex assembly at steps subsequent to TFIIB recruitment (5). Finally, squelching experiments strongly suggest that different classes of activators also require specific cofactors that do not form part of the basal transcriptional machinery (12,29,46).…”

Section: Discussionmentioning

confidence: 99%

Mutational analysis of the transcription activation domain of RelA: identification of a highly synergistic minimal acidic activation module.

Blair¹,

Bogerd²,

Madore³

et al. 1994

Mol. Cell. Biol.

107

124

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The potent C-terminal activation domain of the RelA(p65) subunit of the cellular transcription factor NF-KB is shown to contain several discrete acidic activation modules. These short, -11-amino-acid modules were able to give rise to only a low level of transcription activation when fused to the GAL4 DNA-binding domain as monomers. However, dimers and higher-order multimers activated the transcription of minimal promoter elements as effectively as the full-length RelA or VP16 activation domain. Therefore, this 11-aminoacid ReIA-derived acidic module appears to contain all of the sequence information required to fully activate a target promoter element as long as it is presented in a form that permits functional synergy. Critical primary sequence requirements for acidic activation module function included a core phenylalanine residue and flanking bulky hydrophobic residues. Overall negative charge was necessary but not sufficient for function. While dimeric forms of the 11-amino-acid acidic activation module bound to either TFIIB or TATA-binding protein efficiently in vitro, a similarly charged peptide lacking the core phenylalanine residue failed to interact.Overall, these data demonstrate that the biological activity of the RelA activation domain is dependent on acidic activator sequences that are closely comparable to those detected in the activation domain of the viral VP16 regulatory protein. We hypothesize that the ability of these acidic activators to specifically interact with multiple components of the transcription initiation complex likely underlies the dramatic functional synergy exhibited by this class of activation domains in vivo.

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Section: Discussionmentioning

confidence: 99%

Mutational analysis of the transcription activation domain of RelA: identification of a highly synergistic minimal acidic activation module.

Blair¹,

Bogerd²,

Madore³

et al. 1994

Mol. Cell. Biol.

107

124

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“…These include activation domains in VP16 (30,66), Epstein-Barr virus R (70), and human c-Rel (118) and CTF (57), as well as COUP-TF and other members of the nuclear receptor superfamily (1,49 (112,114). Other experiments indicate that a direct interaction of the activator with TBP and/or TFIIB leads to recruitment of TFIIB into the preinitiation complex (11,57,65,66,105). When the DNA template contains multiple activator-binding sites, acidic activators also stimulate a subsequent step in the assembly of the preinitiation complex involving recruitment of the other general initiation factors and RNA polymerase II (11).…”

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confidence: 99%

“…Other experiments indicate that a direct interaction of the activator with TBP and/or TFIIB leads to recruitment of TFIIB into the preinitiation complex (11,57,65,66,105). When the DNA template contains multiple activator-binding sites, acidic activators also stimulate a subsequent step in the assembly of the preinitiation complex involving recruitment of the other general initiation factors and RNA polymerase II (11). However, none of these studies on the mechanism of activation exclude the possibility that transactivation can also affect a later step in transcription by RNA [98]).…”

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confidence: 99%

“…TFIIH and TFIIJ are the last of these factors to bind to an assembling initiation complex (12,14,26), and TFIIH, also known as BTF2, is the only factor known to possess associated enzymatic activities. These include an ATP-dependent DNA helicase activity (95,96) and a protein kinase activity that can phosphorylate the carboxyterminal heptapeptide repeat domain (CTD) of the largest subunit of RNA polymerase 11 (12,21,68). Evolutionarily related general initiation factors are utilized in the yeast Saccharomyces cerevisiae, and the yeast counterpart of human TFIIH was originally called factor b (21,29).…”

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confidence: 99%

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Binding of basal transcription factor TFIIH to the acidic activation domains of VP16 and p53.

Xiao¹,

Pearson²,

Coulombe³

et al. 1994

Mol. Cell. Biol.

339

274

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Acidic transcriptional activation domains function well in both yeast and mammalian cells, and some have been shown to bind the general transcription factors TFIID and TFIIB. We now show that two acidic transactivators, herpes simplex virus VP16 and human p53, directly interact with the multisubunit human general transcription factor TFIHH and its Saccharomyces cerevisuze counterpart, factor b. The VP16-and p53-binding domains in these factors lie in the p62 subunit of TFIIH and in the homologous subunit, TFB1, of factor b. Point mutations in VP16 that reduce its transactivation activity in both yeast and mammalian cells weaken its binding to both yeast and human TFIIH. This suggests that binding of activation domains to TFIIH is an important aspect of transcriptional activation.Accurate transcription in vitro by human RNA polymerase II involves the general transcription factors TFIIA, TFIIB, TFIID, TFIIE, TFIIF (RAP30 and RAP74), TFIIH (also known as BTF2), and TFIIJ (reviewed in references 13 and 121). Beginning with TFIID, which recognizes the TATA boxes present in many promoters for RNA polymerase II, these factors and RNA polymerase II can be assembled in a defined order onto a promoter (5). TFIIH and TFIIJ are the last of these factors to bind to an assembling initiation complex (12,14,26), and TFIIH, also known as BTF2, is the only factor known to possess associated enzymatic activities. These include an ATP-dependent DNA helicase activity (95, 96) and a protein kinase activity that can phosphorylate the carboxyterminal heptapeptide repeat domain (CTD) of the largest subunit of RNA polymerase 11 (12, 21,68 herpes simplex virus transactivator VP16 (107) and in the N-terminal 73 amino acids of the mammalian tumor suppressor protein p53 (23). The p53 protein has a site-specific DNA-binding domain in its carboxy-terminal portion (101). VP16 does not, by itself, bind specifically to DNA, but instead its amino-terminal portion binds DNA in association with mammalian factors, including the POU homeodomain protein Oct-1 that recognizes octamer sequences in DNA (28,60,102). When fused to the DNA-binding domain of GAL4, the VP16 and p53 activation domains stimulate transcription in yeast and human cells of a gene bearing GAL4-binding sites (9,16,23,74,87,92). These observations imply that common mechanisms for transcriptional activation by acidic activators may exist in fungi and mammals.Many activation domains have been shown to interact with the TATA-box-binding protein (TBP) subunit of TFIID. These include the highly acidic activation domains in VP16 (50,103), p53 (10,67,72,84,97,108),118), and E2F-1 (37), as well as other kinds of activation domains found in the adenovirus activator ElA (48, 62), the Epstein-Barr virus proteins Zta (64) and R (70), the human T-cell leukemia virus type 1 (HTLV-1) activator Taxl (8), the transactivator Tat of human immunodeficiency virus type 1 (HIV-1) (53), and human c-Fos and c-Jun (85), PU-1 (38), and Spl (20). In certain cases, reduced binding of TBP by activation domains wit...

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“…Such Inr elements have been characterized in several TATA-less promoters (Smale and Baltimore, 1989;Bucher, 1990;Javahery et al, 1994;He et al, 1996;Weis and Reinberg, 1997), including the human DNA polymerase b (b-pol) promoter Weis and Reinberg, 1997). In order to achieve the regulated expression of genes utilizing the basal transcription apparatus, several upstream activators are involved in the transcription initiation process (Choy and Green, 1993). The complexity of transcription initiation can be simpli®ed into three distinct steps as described by McClure (1985) for prokaryotic gene regulation.…”

Section: Introductionmentioning

confidence: 99%

Kinetic analysis of Sp1-mediated transcriptional activation of the human DNA polymerase β promoter

Narayan

Wilson

2000

Oncogene

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In the present studies, we have examined the e ect of Sp1 on the activation of the human DNA polymerase b (b-pol), a TATA-less promoter. A HeLa cell nuclear extract (NE) based in vitro runo transcription system of core b-pol promoter human DNA (pbP8) three-step kinetic model of transcription initiation were used to describe the kinetic e ect of Sp1. The results showed that distal Sp1-binding sites in the core b-pol promoter are important for transcriptional activation of the pbP8 promoter. A detailed kinetic analysis showed that Sp1 stimulates the activity of the pbP8 promoter through distal Sp1-binding sites by increasing the amount of recruitment, instead of stimulating the apparent rate of RP c assembly (k 1 ). There was no signi®cant e ect of Sp1 on the apparent rate of open complex (RP o ) formation (k 2 ) or on the apparent rate of promoter clearance (k 3 ) of the pbP8 promoter. These studies de®ne the kinetic mechanisms by which Sp1 may regulate the rate of transcript formation of the pbP8 promoter, and these results may have implications for Sp1 regulation of TATA-less promoters. Oncogene (2000) 19, 4729 ± 4735.

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Eukaryotic activators function during multiple steps of preinitiation complex assembly

Cited by 285 publications

References 50 publications

Mutational analysis of the transcription activation domain of RelA: identification of a highly synergistic minimal acidic activation module.

Mutational analysis of the transcription activation domain of RelA: identification of a highly synergistic minimal acidic activation module.

Binding of basal transcription factor TFIIH to the acidic activation domains of VP16 and p53.

Kinetic analysis of Sp1-mediated transcriptional activation of the human DNA polymerase β promoter

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