Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The early E2 (E2E) promoter of adenovirus type 2 possesses a TATA-like element and binding sites for the factors E2F and ATF. This promoter is transcribed by RNA polymerase II in high salt nuclear extracts, but by RNA polymerase III in standard nuclear extracts, as judged by sensitivity to low and high, respectively, concentrations of alpha-amanitin. Transcription by the two RNA polymerases initiated at the same site and depended, in both cases, on the TATA-like sequence and upstream elements. However, RNA polymerase III transcripts, unlike those synthesized by RNA polymerase II, terminated at two runs of Ts downstream of the initiation site. Although they are not essential, sequences downstream of the initiation site increased the efficiency of E2E transcription by RNA polymerase III. Such RNA polymerase III dependent transcription required a subpopulation of the general transcription factor, TFIID: TFIID that binds weakly to phosphocellulose (0.3 M eluate) complemented a TFIID-depleted extract to restore RNAp III transcription, whereas TFIID tightly associated with phosphocellulose (1 M eluate) was unable to do so.
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PMID:Specific transcription from the adenovirus E2E promoter by RNA polymerase III requires a subpopulation of TFIID. 145 34

Host cell RNA synthesis is inhibited by poliovirus infection. We have studied the mechanism of poliovirus-induced inhibition of RNA polymerase II-mediated transcription by using the adenovirus early region 3 (E3) promoter. In vitro transcription from the E3 promoter was severely inhibited in extracts prepared from poliovirus-infected HeLa cells. Four regions in the E3 promoter have been shown to serve as binding sites for cellular transcription factors. These regions contain binding sites for transcription factors NF-1 (site IV), AP-1 (site III), CREB/ATF (site II), and the TATA factor (site I). Binding to these four regions was not significantly altered by poliovirus infection as assayed by DNase I footprinting analysis; furthermore, gel retardation assays failed to reveal dramatic differences in the total amount of CREB/ATF-, AP-1-, and NF-1-binding activity present in mock- or poliovirus-infected cell extracts. Gel retardation assays, however, did reveal significant qualitative differences in the DNA-protein complexes formed with a CREB/ATF-binding site in extracts prepared from poliovirus-infected cells as compared to mock-infected cell extracts. Radioimmunoprecipitation reactions performed with antiserum against CREB/ATF revealed a severe reduction in a phosphorylated form of the protein present in poliovirus-infected cell extracts. However, in vitro kinase reactions demonstrated that mock- and poliovirus-infected cell extracts contained similar levels of CREB/ATF. Expression from the E3 promoter was shown to be activated by CREB/ATF in vivo; this induction was dependent upon the phosphorylation of CREB/ATF. Thus, we propose that poliovirus infection inhibits transcription from the E3 promoter, at least in part, through the dephosphorylation of CREB/ATF.
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PMID:Loss of a phosphorylated form of transcription factor CREB/ATF in poliovirus-infected cells. 216 27

The mammalian activator protein ATF stimulates transcription from the adenovirus E4 promoter by binding to multiple upstream promoter and enhancer elements. DNAase footprint analyses have revealed that there are cooperative interactions between ATF and TFIID (the mammalian TATA factor) when both are bound simultaneously to the promoter and that these interactions in turn facilitate promoter recognition by RNA polymerase II and the general initiation factors TFIIB and TFIIE. However, the complex of TFIID and the other general factors is stable following oligonucleotide-mediated dissociation of ATF from the complete preinitiation complex. These results indicate that TFIID is a direct target for ATF, that these interactions facilitate assembly of a complete preinitiation complex, and that the role of ATF might be transient.
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PMID:Transcription factor ATF interacts with the TATA factor to facilitate establishment of a preinitiation complex. 341 54

In the accompanying paper (Horikoshi et al., 1988) the interaction between ATF and the general transcription initiation factors was analyzed by DNAase I footprinting experiments. Here, we use transcription assays to investigate the role of ATF in the assembly of a functional preinitiation complex. Addition of an oligonucleotide containing an ATF binding site inhibits E4 transcription by sequestering ATF. However, following preincubation of the E4 promoter in the nuclear extract, transcription is refractory to inhibition by the ATF oligonucleotide. Formation of this oligonucleotide-refractory complex occurs at an early stage in the overall transcription initiation reaction and is dependent upon ATF and the general transcription factors RNA polymerase II, TFIIB, and TFIID. This latter result suggests that the assembly and maintenance of a functional preinitiation complex involves cooperative interactions among the various transcription factors. The general transcription factor TFIIE, although required for transcriptional activity, is not involved in the assembly of an ATF oligonucleotide-refractory complex. Our results support the possibility that ATF may be required only transiently for assembly of a functional preinitiation complex.
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PMID:Analysis of the role of the transcription factor ATF in the assembly of a functional preinitiation complex. 341 55

Changes in genetic programming of a cell are brought about by modulating the activity of transcription factors which control the initiation of gene transcription by RNA polymerase II. Phosphorylation of transcription factors as a regulatory mechanism is both rapid and readily reversible. Moreover, because a transcription factor can be targeted by several protein kinases and phosphatases, this covalent modification can effectively integrate information carried by multiple signal transduction pathways, thereby providing a palette for great versatility and flexibility in the regulation of gene expression. The CREB/ATF family of transcription factors serves as a paradigm illustrating the phosphorylation-mediated transfer of regulatory information from the cell surface to the nucleus.
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PMID:The CREB/ATF family of transcription factors: modulation by reversible phosphorylation. 784 13

The core promoter of the human DNA beta-polymerase (beta-pol) gene is regulated by proteins binding at 3 GC boxes and the single activating transcription factor/cAMP response element (ATF/CRE) centered at -45; the central 8 residues of this ATF/CRE match the ATF/CRE consensus sequence, TGACGTCA. Previously, we purified a beta-pol promoter ATF/CRE-binding protein (named palindrome-binding protein or PBP) from bovine testes and found that this protein is a beta-pol promoter transcriptional activator in vitro using a HeLa nuclear extract transcription system (Widen, S. G., and Wilson, S. H. (1991) Biochemistry 30, 6296-6305). In this study, we determined the mechanism of in vitro transcriptional activation by this purified PBP. We used a PBP-depleted HeLa nuclear extract transcription system with an artificial promoter containing a solitary activator element corresponding to the entire 22-nucleotide beta-pol promoter ATF/CRE-binding site. Kinetic analyses of the 180-nucleotide run-off product formation indicated that stimulation of transcriptional activity by PBP was due entirely to an increase in the rate constant for promoter clearance. Thus, under our conditions, the purified PBP had no effect on the rate of closed preinitiation complex formation or for the closed complex to open complex transition. Instead, the rate of productive initiation leading to the 180-nucleotide transcript was stimulated by PBP. We found that the rate of closed preinitiation complex formation was not in rapid equilibrium with promoter and RNA polymerase II, in contrast to the model with prokaryotic RNA polymerase transcription. The results also indicated that PBP binding to the ATF/CRE is required for the stimulation of promoter clearance. These studies define the kinetic mechanism of a purified ATF/CRE-binding protein in stimulation of the in vitro transcription of a designed mammalian promoter.
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PMID:RNA polymerase II transcription. Rate of promoter clearance is enhanced by a purified activating transcription factor/cAMP response element-binding protein. 817 88

We have developed a simple method to purify sequence-specific DNA-binding proteins directly from crude cell extracts by using DNA affinity latex beads. The method enabled us to purify not only DNA-binding proteins, but also their associated proteins. Using beads bearing the ATF/E4TF3 site from the adenovirus E4 gene promoter, a protein kinase activity was copurified with the ATF/E4TF3 family. We found that the kinase interacted with ATF1 in vitro efficiently. The kinase did not bind directly to DNA. The kinase mainly phosphorylated ATF1 on serine 36, which was one of target amino acids for casein kinase (CK) II. Biological features of the kinase were the same as those of CKII and an anti-CKII serum reacted with the kinase, indicating that the kinase was CKII. Moreover, it was clearly shown that one of CKII subunits, the CKII alpha protein bound to glutathione-S-transferase (GST) fusion ATF1 but not GST in vitro. It has been reported that a specific CKII inhibitor, 5,6-dichloro-1-beta-D-ribo-furanosylbenzimidazole (DRB) inhibits transcription by RNA polymerase II [Zandomeni et al., (1986) J. Biol. Chem. 261, 3414-3419]. Taken together, these results suggest that ATF/E4TF3 may recruit the CKII activity to a transcription initiation machinery and stimulate transcription.
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PMID:Copurification of casein kinase II with transcription factor ATF/E4TF3. 860 Apr 55

The Tax transactivator protein of human T-cell leukemia virus type 1 (HTLV-1) plays a central role in the activation of viral gene expression. In addition, Tax is capable of activating the expression of specific cellular genes and is involved in the transformation of T-lymphocytes resulting in the development of adult T-cell leukemia. Tax is a phosphoprotein that colocalizes in nuclear bodies with RNA polymerase II, splicing complexes, and specific transcription factors including members of the ATF/CREB and NF-kappaB families. In this study, we identified adjacent serine residues at positions 300 and 301 in the carboxy terminus of Tax as the major sites for phosphorylation. Phosphorylation of at least one of these serine residues is required for Tax localization in nuclear bodies and for Tax-mediated activation of gene expression via both the ATF/CREB and NF-kappaB pathways. Introduction of amino acid substitutions which are phosphoserine mimetics at positions 300 and 301 restored the ability of a phosphorylation-defective Tax mutant to form nuclear bodies and to activate gene expression. These studies define sites for regulatory phosphorylation events in Tax which are critical for its ability to activate gene transcription.
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PMID:Phosphorylation of the human T-cell leukemia virus type 1 transactivator tax on adjacent serine residues is critical for tax activation. 984 80

Transcription of the human 7SL RNA gene by RNA polymerase III depends on the concerted action of transcription factors binding to the gene-internal and gene-external parts of its promoter. Here, we investigated which transcription factors interact with the human 7SL RNA gene promoter and which are required for transcription of the human 7SL RNA gene. A-box/B-box elements were previously identified in 5S RNA, tRNA, and virus associated RNA genes and are recognized by transcription factor IIIC (TFIIIC). The gene-internal promoter region of the human 7SL RNA gene shows only limited similarity to those elements. Nevertheless, competition experiments and the use of highly enriched factor preparations demonstrate that TFIIIC is required for human 7SL transcription. The gene-external part of the promoter includes an authentic cAMP-responsive element previously identified in various RNA polymerase II promoters. Here we demonstrate that members of the activating transcription factor/cyclic AMP-responsive element binding protein (ATF/CREB) transcription factor family bind specifically to this element in vitro. However, the human 7SL RNA gene is not regulated by cAMP in vivo. Furthermore, in vitro transcription of the gene does not depend on ATF/CREB transcription factors. It rather appears that a transcription factor with DNA-binding characteristics like ATF/CREB proteins but otherwise different properties is required for human 7SL RNA transcription.
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PMID:Analysis of transcription factors binding to the human 7SL RNA gene promoter. 1059 6

BRCA1, a breast and ovarian cancer susceptibility gene, encodes a 220-kDa protein whose precise biochemical function remains unclear. BRCA1 contains an N-terminal RING finger that mediates protein-protein interaction. The C-terminal domain of BRCA1 (BRCT) can activate transcription and interacts with RNA polymerase holoenzyme. Using the yeast two-hybrid system, we identified an interaction between the BRCA1 RING finger and ATF1, a member of the cAMP response element-binding protein/activating transcription factor (CREB/ATF) family. We demonstrate that BRCA1 and ATF1 can physically associate in vitro, in yeast, and in human cells. BRCA1 stimulated transcription from a cAMP response element reporter gene in transient transfections. BRCA1 also stimulated transcription from a natural promoter, that of tumor necrosis factor-alpha, in a manner dependent on the integrity of the cAMP response element. These results implicate BRCA1 in transcriptional activation of ATF1 target genes, some of which are involved in the transcriptional response to DNA damage.
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PMID:BRCA1 physically and functionally interacts with ATF1. 1094 75


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