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Downregulation of miR-144 by triptolide enhanced p85α-PTEN complex formation causing S phase arrest of human nasopharyngeal carcinoma cells. Eur J Pharmacol 2019; 855:137-148. [PMID: 31059711 DOI: 10.1016/j.ejphar.2019.04.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/26/2019] [Accepted: 04/30/2019] [Indexed: 12/15/2022]
Abstract
Selective pharmacologic targeting of cell cycle regulators is a potent anti-cancer therapeutic strategy. Here, we show that caspase-3-mediated p21 cleavage involves p53 independent of triptolide (TPL)-induced S phase arrest in human type 1 nasopharyngeal carcinoma (NPC) cells. Coimmunoprecipitation studies demonstrated that TPL causes S phase cell cycle arrest by suppressing the formation of cyclin A-phosphor (p)-cyclin-dependent kinas 2 (CDK2) (Thr 39) complexes. Ectopic expression of constitutively active protein kinase B1 (Akt1) blocks the induction of S phase arrest and the suppression of cyclin A expression and CDK2 Thr 39 phosphorylation by TPL. Expression of the phosphomimetic mutant CDK2 (T39E) rescues the cells from TPL-induced S phase arrest, whereas phosphorylation-deficient CDK2 (T39A) expression regulates cell growth with significant S phase arrest and enhances TPL-triggered S phase arrest. Treatment with TPL induces an increase in the formation of complexes between unphosphorylated phosphatase and tensin homolog deleted from chromosome 10 (PTEN) and p85α in the plasma membrane. Decreased microRNA (miR)-144 expression and increased PTEN expression after TPL treatment were demonstrated, and TPL-enhanced p85α-PTEN complexes and inhibitory effects on Akt (Ser 473) phosphorylation and S phase arrest were suppressed by ectopic PTEN short hairpin RNA or miR-144 expression. Knockdown of endogenous miR-144 by miR-144 Trap upregulated PTEN expression and accordingly enhanced p85α-PTEN complex formation and S phase arrest. Collectively, the effect of TPL on S phase arrest in human NPC cells is likely to enhance the p85α-PTEN interaction in the plasma membrane by suppressing miR-144 expression, resulting in the attenuation of cyclin A-p-CDK2 (Thr 39) complex formation via Akt inactivation.
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2
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Goodrich JA, Tjian R. Unexpected roles for core promoter recognition factors in cell-type-specific transcription and gene regulation. Nat Rev Genet 2010; 11:549-58. [PMID: 20628347 DOI: 10.1038/nrg2847] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The eukaryotic core promoter recognition complex was generally thought to play an essential but passive role in the regulation of gene expression. However, recent evidence now indicates that core promoter recognition complexes together with 'non-prototypical' subunits may have a vital regulatory function in driving cell-specific programmes of transcription during development. Furthermore, new roles for components of these complexes have been identified beyond development; for example, in mediating interactions with chromatin and in maintaining active gene expression across cell divisions.
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Affiliation(s)
- James A Goodrich
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Colorado 80309, USA
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3
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Ghazy MA, Brodie SA, Ammerman ML, Ziegler LM, Ponticelli AS. Amino acid substitutions in yeast TFIIF confer upstream shifts in transcription initiation and altered interaction with RNA polymerase II. Mol Cell Biol 2004; 24:10975-85. [PMID: 15572698 PMCID: PMC533996 DOI: 10.1128/mcb.24.24.10975-10985.2004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcription factor IIF (TFIIF) is required for transcription of protein-encoding genes by eukaryotic RNA polymerase II. In contrast to numerous studies establishing a role for higher eukaryotic TFIIF in multiple steps of the transcription cycle, relatively little has been reported regarding the functions of TFIIF in the yeast Saccharomyces cerevisiae. In this study, site-directed mutagenesis, plasmid shuffle complementation assays, and primer extension analyses were employed to probe the functional domains of the S. cerevisiae TFIIF subunits Tfg1 and Tfg2. Analyses of 35 Tfg1 alanine substitution mutants and 19 Tfg2 substitution mutants identified 5 mutants exhibiting altered properties in vivo. Primer extension analyses revealed that the conditional growth properties exhibited by the tfg1-E346A, tfg1-W350A, and tfg2-L59K mutants were associated with pronounced upstream shifts in transcription initiation in vivo. Analyses of double mutant strains demonstrated functional interactions between the Tfg1 mutations and mutations in Tfg2, TFIIB, and RNA polymerase II. Importantly, biochemical results demonstrated an altered interaction between mutant TFIIF protein and RNA polymerase II. These results provide direct evidence for the involvement of S. cerevisiae TFIIF in the mechanism of transcription start site utilization and support the view that a TFIIF-RNA polymerase II interaction is a determinant in this process.
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Affiliation(s)
- Mohamed A Ghazy
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, NY 14214-3000, USA
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4
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Kamada K, Roeder RG, Burley SK. Molecular mechanism of recruitment of TFIIF- associating RNA polymerase C-terminal domain phosphatase (FCP1) by transcription factor IIF. Proc Natl Acad Sci U S A 2003; 100:2296-9. [PMID: 12591941 PMCID: PMC151334 DOI: 10.1073/pnas.262798199] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
After mRNA transcription termination in eukaryotes, the hyperphosphorylated form of RNA polymerase II (pol II0) must be recycled by TFIIF-associating C-terminal domain phosphatase (FCP1), the phosphatase responsible for dephosphorylating the C-terminal domain of the largest polymerase subunit. Transcription factor (TF)-IIF stimulates the activity of FCP1, and the RNA polymerase II-associating protein 74 subunit of TFIIF forms a complex with FCP1 in both human and yeast. Here, we report a cocrystal structure of the winged-helix domain of human RNA polymerase II-associating protein 74 bound to the alpha-helical C terminus of human FCP1 (residues 944-961). These results illustrate the molecular mechanism by which TFIIF efficiently recruits FCP1 to the pol II transcription machinery for recycling of the polymerase.
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Affiliation(s)
- Katsuhiko Kamada
- Laboratory of Molecular Biophysics and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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5
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Mizuguchi G, Vassilev A, Tsukiyama T, Nakatani Y, Wu C. ATP-dependent nucleosome remodeling and histone hyperacetylation synergistically facilitate transcription of chromatin. J Biol Chem 2001; 276:14773-83. [PMID: 11279013 DOI: 10.1074/jbc.m100125200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Drosophila nucleosome remodeling factor (NURF) is an ISWI-containing protein complex that facilitates nucleosome mobility and transcriptional activation in an ATP-dependent manner. Numerous studies have implicated histone acetylation in transcriptional activation. We investigated the relative contributions of these two chromatin modifications to transcription in vitro of a chromatinized adenovirus E4 minimal promoter that contains binding sites for the GAL4-VP16 activator. We found that NURF could remodel chromatin and stimulate transcription irrespective of the acetylation status of histones. In contrast, hyperacetylation of histones in the absence of NURF was unable to stimulate transcription, suggesting that NURF-dependent chromatin remodeling is an obligatory step in E4 promoter activation. When chromatin templates were first hyperacetylated and then incubated with NURF, significantly greater transcription stimulation was observed. The results suggest that changes in chromatin induced by acetylation of histones and the mobilization of nucleosomes by NURF combine synergistically to facilitate transcription. Experiments using single and multiple rounds of transcription indicate that these chromatin modifications stimulate transcription preinitiation as well as reinitiation.
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Affiliation(s)
- G Mizuguchi
- Laboratory of Molecular Cell Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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6
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Kamada K, De Angelis J, Roeder RG, Burley SK. Crystal structure of the C-terminal domain of the RAP74 subunit of human transcription factor IIF. Proc Natl Acad Sci U S A 2001; 98:3115-20. [PMID: 11248041 PMCID: PMC30616 DOI: 10.1073/pnas.051631098] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2000] [Indexed: 11/18/2022] Open
Abstract
The x-ray structure of a C-terminal fragment of the RAP74 subunit of human transcription factor (TF) IIF has been determined at 1.02-A resolution. The alpha/beta structure is strikingly similar to the globular domain of linker histone H5 and the DNA-binding domain of hepatocyte nuclear factor 3gamma (HNF-3gamma), making it a winged-helix protein. The surface electrostatic properties of this compact domain differ significantly from those of bona fide winged-helix transcription factors (HNF-3gamma and RFX1) and from the winged-helix domains found within the RAP30 subunit of TFIIF and the beta subunit of TFIIE. RAP74 has been shown to interact with the TFIIF-associated C-terminal domain phosphatase FCP1, and a putative phosphatase binding site has been identified within the RAP74 winged-helix domain.
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Affiliation(s)
- K Kamada
- Laboratories of Molecular Biophysics and Biochemistry and Molecular Biology, and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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7
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Abstract
The HIV-1 Tat protein is an RNA-binding transcriptional transactivator. Recent findings suggest that Tat associates with a cellular kinase that phosphorylates the carboxyl-terminal domain of the largest subunit of RNA polymerase II. Here we review, in brief, the role of Tat-associated kinase in Tat-activated transcription. We discuss evidence that suggests involvement of TFIIH and/or P-TEFb.
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Affiliation(s)
- K T Jeang
- Molecular Virology Section, Laboratory of Molecular Microbiology, NIAID, NIH, Bethesda, MD 20892-0460, USA.
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8
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Yan Q, Moreland RJ, Conaway JW, Conaway RC. Dual roles for transcription factor IIF in promoter escape by RNA polymerase II. J Biol Chem 1999; 274:35668-75. [PMID: 10585446 DOI: 10.1074/jbc.274.50.35668] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription factor (TF) IIF is a multifunctional RNA polymerase II transcription factor that has well established roles in both transcription initiation, where it functions as a component of the preinitiation complex and is required for formation of the open complex and synthesis of the first phosphodiester bond of nascent transcripts, and in transcription elongation, where it is capable of interacting directly with the ternary elongation complex and stimulating the rate of transcription. In this report, we present evidence that TFIIF is also required for efficient promoter escape by RNA polymerase II. Our findings argue that TFIIF performs dual roles in this process. We observe (i) that TFIIF suppresses the frequency of abortive transcription by very early RNA polymerase II elongation intermediates by increasing their processivity and (ii) that TFIIF cooperates with TFIIH to prevent premature arrest of early elongation intermediates. In addition, our findings argue that two TFIIF functional domains mediate TFIIF action in promoter escape. First, we observe that a TFIIF mutant selectively lacking elongation activity supports TFIIH action in promoter escape, but is defective in suppressing the frequency of abortive transcription by very early RNA polymerase II elongation intermediates. Second, a TFIIF mutant selectively lacking initiation activity is more active than wild type TFIIF in increasing the processivity of very early elongation intermediates, but is defective in supporting TFIIH action in promoter escape. Taken together, our findings bring to light a function for TFIIF in promoter escape and support a role for TFIIF elongation activity in this process.
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Affiliation(s)
- Q Yan
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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9
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Conaway JW, Dvir A, Moreland RJ, Yan Q, Elmendorf BJ, Tan S, Conaway RC. Mechanism of promoter escape by RNA polymerase II. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1999; 63:357-64. [PMID: 10384300 DOI: 10.1101/sqb.1998.63.357] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- J W Conaway
- Howard Hughes Medical Institute, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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10
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Dvir A, Conaway RC, Conaway JW. A role for TFIIH in controlling the activity of early RNA polymerase II elongation complexes. Proc Natl Acad Sci U S A 1997; 94:9006-10. [PMID: 9256425 PMCID: PMC23002 DOI: 10.1073/pnas.94.17.9006] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/1997] [Indexed: 02/05/2023] Open
Abstract
TFIIH is a multifunctional RNA polymerase II transcription factor that possesses DNA-dependent ATPase, DNA helicase, and protein kinase activities. Previous studies have established that TFIIH enters the preinitiation complex and fulfills a critical role in initiation by catalyzing ATP-dependent formation of the open complex prior to synthesis of the first phosphodiester bond of nascent transcripts. In this report, we present direct evidence that TFIIH also controls RNA polymerase II activity at a postinitiation stage of transcription, by preventing premature arrest by very early elongation complexes just prior to their transition to stably elongating complexes. Unexpectedly, we observe that TFIIH is capable of entering the transcription cycle not only during assembly of the preinitiation complex but also after initiation and synthesis of as many as four to six phosphodiester bonds. These findings shed new light on the role of TFIIH in initiation and promoter escape and reveal an unanticipated flexibility in the ability of TFIIH to interact with RNA polymerase II transcription intermediates prior to, during, and immediately after initiation.
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Affiliation(s)
- A Dvir
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, OK 73104, USA
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11
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Reines D, Dvir A, Conaway JW, Conaway RC. Assays for investigating transcription by RNA polymerase II in vitro. Methods 1997; 12:192-202. [PMID: 9237163 DOI: 10.1006/meth.1997.0471] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
With the availability of the general initiation factors (TFIIB, TFIID, TFIIE, TFIIF, and TFIIH), it is now possible to investigate aspects of the mechanism of eukaryotic messenger RNA synthesis in purified, reconstituted RNA polymerase II transcription systems. Rapid progress in these investigations has been spurred by use of a growing number of assays that are proving valuable not only for dissecting the molecular mechanisms of transcription initiation and elongation by RNA polymerase II, but also for identifying and purifying novel transcription factors that regulate polymerase activity. Here we describe a variety of these assays and discuss their utility in the analysis of transcription by RNA polymerase II.
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Affiliation(s)
- D Reines
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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12
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Frank DJ, Tyree CM, George CP, Kadonaga JT. Structure and function of the small subunit of TFIIF (RAP30) from Drosophila melanogaster. J Biol Chem 1995; 270:6292-7. [PMID: 7890767 DOI: 10.1074/jbc.270.11.6292] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To study the mechanism of basal transcription by RNA polymerase II, a cDNA encoding the Drosophila homologue of the small subunit of TFIIF (also referred to as TFIIF30, RAP30, factor 5b, and gamma) was isolated. The Drosophila TFIIF30 gene is located at region 86C on the right arm of the third chromosome. The protein encoded by the cDNA, termed dTFIIF30, was synthesized in Escherichia coli and purified to greater than 95% homogeneity. In reconstituted transcription reactions with purified basal factors, the specific activity of dTFIIF30 was identical to that of its human homologue. Moreover, a carboxyl-terminal fragment, designated dF30(119-276), which contains the carboxyl-terminal 158 amino acid residues of dTFIIF30, was found to possess approximately 50% of the transcriptional activity as full-length dTFIIF30. The interaction of dTFIIF30 with the large subunit of TFIIF (also referred to as TFIIF74, RAP74, factor 5a, and beta) was investigated by glycerol gradient sedimentation analyses. In these experiments, dTFIIF30, but not dF30(119-276), assembled into a stable heteromeric complex with TFIIF74. These results, combined with those of previous work on TFIIF, support a model for TFIIF30 function in which the carboxylterminal region constitutes a functional domain that can interact with RNA polymerase II to mediate basal transcription, whereas the amino terminus comprises a domain that interacts with TFIIF74.
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Affiliation(s)
- D J Frank
- Department of Biology, University of California at San Diego, La Jolla 92093-0347
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13
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Role of core promoter structure in assembly of the RNA polymerase II preinitiation complex. A common pathway for formation of preinitiation intermediates at many TATA and TATA-less promoters. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)47233-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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14
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An oligomeric form of the large subunit of transcription factor (TF) IIE activates phosphorylation of the RNA polymerase II carboxyl-terminal domain by TFIIH. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32056-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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15
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Kephart D, Wang B, Burton Z, Price D. Functional analysis of Drosophila factor 5 (TFIIF), a general transcription factor. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36864-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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16
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Narayan S, Widen S, Beard W, Wilson S. RNA polymerase II transcription. Rate of promoter clearance is enhanced by a purified activating transcription factor/cAMP response element-binding protein. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)99940-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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17
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Bradsher JN, Tan S, McLaury HJ, Conaway JW, Conaway RC. RNA polymerase II transcription factor SIII. II. Functional properties and role in RNA chain elongation. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74432-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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18
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Serizawa H, Conaway JW, Conaway RC. Phosphorylation of C-terminal domain of RNA polymerase II is not required in basal transcription. Nature 1993; 363:371-4. [PMID: 8497323 DOI: 10.1038/363371a0] [Citation(s) in RCA: 139] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Phosphorylation of the heptapeptide repeats in the C-terminal domain (CTD) of the largest subunit of RNA polymerase II has been widely proposed as an essential step in transcription initiation on the basis of findings indicating (1) that the CTDs of RNA polymerase II molecules actively engaged in transcription are highly phosphorylated; (2) that polymerase molecules containing non-phosphorylated CTDs preferentially enter the preinitiation complex where they are subsequently phosphorylated; and (3) that essential initiation factors b from yeast, delta from rat, and BTF2(TFIIH) from human cells have closely associated CTD-kinase activities. Here we take advantage of a highly purified enzyme system which supports both CTD phosphorylation and basal transcription to test this hypothesis directly. Using the isoquinoline sulphonamide derivative H-8, which is a potent inhibitor of CTD kinase, we show that basal transcription occurs in the absence of CTD phosphorylation.
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Affiliation(s)
- H Serizawa
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City 73104
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19
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Mechanism of assembly of the RNA polymerase II preinitiation complex. Transcription factors delta and epsilon promote stable binding of the transcription apparatus to the initiator element. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50211-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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20
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Conaway R, Bradsher J, Conaway J. Mechanism of assembly of the RNA polymerase II preinitiation complex. Evidence for a functional interaction between the carboxyl-terminal domain of the largest subunit of RNA polymerase II and a high molecular mass form of the TATA factor. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42467-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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21
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Aso T, Vasavada HA, Kawaguchi T, Germino FJ, Ganguly S, Kitajima S, Weissman SM, Yasukochi Y. Characterization of cDNA for the large subunit of the transcription initiation factor TFIIF. Nature 1992; 355:461-4. [PMID: 1734283 DOI: 10.1038/355461a0] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
At least six chromatographically resolvable general transcription factors may participate in accurate initiation by RNA polymerase II in HeLa cell-derived systems. TFIIF (also termed FC, RAP30/74 and beta/gamma) can bind directly to RNA polymerase II in solution and decrease the affinity of RNA polymerase II for nonspecific DNA. From studies on the kinetics of transcription initiation, on the composition of transcription initiation complexes fractionated by acrylamide gel electrophoresis, and on template competition experiments, TFIIF is known to act at an intermediate stage in initiation complex formation. It acts after TFIID firmly associates with DNA, but coincidentally with or immediately after RNA polymerase II binding to DNA, and before the recruitment of factor TFIIE. TFIIF may or may not have DNA helicase activity. The small subunit (RAP30) of TFIIF has been cloned and shows some amino-acid sequence homology to bacterial sigma factors. We have partially sequenced the RAP74 protein from purified HeLa cells, cloned its complementary DNA and shown that its translation product can interact with RAP30 in vitro as well as in vivo. The cDNA predicts an amino-acid sequence that lacks obvious DNA or RNA helicase motifs. It has regions rich in charged amino acids, including segments containing a higher content of acidic amino acids than are found in strong transcriptional activators such as VP16.
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Affiliation(s)
- T Aso
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510
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22
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Schnapp A, Grummt I. Transcription complex formation at the mouse rDNA promoter involves the stepwise association of four transcription factors and RNA polymerase I. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54269-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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23
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Purification and interaction properties of the human RNA polymerase B(II) general transcription factor BTF2. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54801-8] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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24
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Burton N, Cavallini B, Kanno M, Moncollin V, Egly JM. Expression in Escherichia coli: purification and properties of the yeast general transcription factor TFIID. Protein Expr Purif 1991; 2:432-41. [PMID: 1821818 DOI: 10.1016/1046-5928(91)90105-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A T7 RNA polymerase expression system has been used for the efficient expression of the yeast RNA polymerase general transcription factor TFIID (TFIIDY), the TATA-box factor (previously called BTF1) in Escherichia coli. Expression of the gene was performed at 25 degrees C instead of 37 degrees C to increase the total amount of soluble TFIIDY. Soluble TFIIDY was purified in three chromatographic steps and was eluted from the final column, a heparin-5PW HPLC column, in two peaks at 0.38 M (peak I) and 0.42 M (peak II) KCl in which this protein was 52% and greater than 95% pure, respectively. The protein in both peaks was active in an in vitro transcription assay. However, while TFIIDY from peak II was essentially indistinguishable from the material isolated from yeast, the protein of peak I differed in a number of biochemical characteristics, having a lower specific activity in an in vitro transcription assay and displaying an altered pattern of bands in a DNA band shift assay. Despite these differences, the proteins in both peaks have identical molecular weights on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, have indistinguishable N-terminal amino acid sequences, and apparently exist as monomers under the conditions used for the heparin-5PW chromatography.
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Affiliation(s)
- N Burton
- Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Faculté de Médecine, Strasbourg, France
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25
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26
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Reines D. RNA polymerase II elongation complex. Elongation complexes purified using an anti-RNA antibody do not contain initiation factor alpha. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99254-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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27
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Vos JC, Sasker M, Stunnenberg HG. Promoter melting by a stage-specific vaccinia virus transcription factor is independent of the presence of RNA polymerase. Cell 1991; 65:105-13. [PMID: 2013091 DOI: 10.1016/0092-8674(91)90412-r] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fractionation of an extract prepared from HeLa cells infected with vaccinia virus resulted in the separation of factors involved in vaccinia virus intermediate transcription. Two activities, VITF-A and VITF-B, in addition to the viral RNA polymerase are necessary and sufficient to direct intermediate transcription in vitro. VITF-B confers intermediate promoter specificity to an early-specific extract prepared from virus particles. A committed complex between VITF-B and the template can sequester VITF-A and RNA polymerase into a pre-initiation complex. VITF-B is further able to melt the promoter at the start site of transcription. Open complex formation is stimulated by ATP. In contrast to prokaryotic and eukaryotic pol III transcription, promoter melting is independent of the presence of RNA polymerase.
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Affiliation(s)
- J C Vos
- European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany
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28
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Transcription initiated by RNA polymerase II and transcription factors from liver. Structure and action of transcription factors epsilon and tau. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)89521-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Wampler SL, Tyree CM, Kadonaga JT. Fractionation of the general RNA polymerase II transcription factors from Drosophila embryos. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)45349-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Conaway JW, Conaway RC. An RNA polymerase II transcription factor shares functional properties with Escherichia coli sigma 70. Science 1990; 248:1550-3. [PMID: 2193400 DOI: 10.1126/science.2193400] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A mammalian transcription factor, which, along with other factors, is essential for accurate initiation of transcription from promoters by RNA polymerase II, has been found to regulate the interaction of polymerase and DNA. This factor, designated beta gamma, drastically reduces the affinity of RNA polymerase II for free DNA containing either promoter or nonpromoter sequences. In this respect, beta gamma functions as does the bacterial transcription initiation factor sigma 70, which expedites the binding of Escherichia coli RNA polymerase to promoters in part by accelerating dissociation of the polymerase from nonpromoter sites in DNA.
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Affiliation(s)
- J W Conaway
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City 73104
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Transcription initiated by RNA polymerase II and purified transcription factors from liver. Cooperative action of transcription factors tau and epsilon in initial complex formation. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39149-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Conaway JW, Travis E, Conaway RC. Transcription initiated by RNA polymerase II and purified transcription factors from liver. A complex set of promoter sequences governs formation of the initial complex. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39151-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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