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)

All genes encoding proteins in eukaryotes are transcribed by RNA polymerase II. The first step in analyzing transcriptional regulation requires understanding the general mechanisms of RNA polymerase II-specific gene transcription. The basal promoter, a template containing a TATA box devoid of upstream regulatory sequences, has been used to identify and characterize the factors which, together with RNA polymerase II, govern transcription in mammalian systems: TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIG, TFIIH, and TFIIJ. Interactions between regulatory transcription factors and basal elements of the transcriptional machinery affect the transcriptional rate in a positive or negative fashion. As these multiple proteins are purified, and their coding sequences are isolated, we come closer to reproducing these processes in vitro with pure components, and thus to elucidating the complex interactions among them.
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PMID:The basic RNA polymerase II transcriptional machinery. 163 39

Transcription factor TFIIA, defined by its role in transcription by RNA polymerase II, is also involved in RNA polymerase III transcription of mammalian U6 small nuclear RNA genes. This finding was substantiated by experimental evidence including (i) extensive copurification of an activity required for U6 transcription with TFIIA, (ii) the comparable molecular dimensions of this activity and TFIIA, (iii) the identical heat stability of both activities, and (iv) functional analyses revealing that TFIIA facilitates the interaction of TFIID with the TATA box of the U6 gene. As was shown previously for TFIID, TFIIA is the second basal transcription factor which could be demonstrated to be involved in gene expression by two different RNA polymerases.
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PMID:TFIIA is required for in vitro transcription of mammalian U6 genes by RNA polymerase III. 164 19

Two new factors required for transcription of class II genes have been identified. These factors, TFIIH and TFIIJ, were required together with the previously described general factors (TFIIA, TFIIB, TFIID, TFIIE, and TFIIF) and RNA polymerase II for transcription of different class II genes. TFIIH was extensively purified, and the activity appeared to coelute with polypeptides of 33 and 95 kDa. The role of TFIIH and TFIIJ in preinitiation complex assembly was analyzed using mobility shift assays. It was found that TFIIH and TFIIJ association with the preinitiation complex was ordered and required the previous assembly of a preinitiation complex intermediate containing factors IID, IIB, IIF, IIE, and RNA polymerase II. A model for the ordered assembly of the general factors and RNA polymerase II is presented.
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PMID:Factors involved in specific transcription by mammalian RNA polymerase II. Identification and characterization of factor IIH. 173 73

RAP30/74 (also known as TFIIF, beta gamma and FC is one of several general factors required for initiation by RNA polymerase II. The small RAP30 subunit of RAP30/74 binds directly to polymerase and appears structurally and functionally homologous to bacterial sigma factors in their RNA polymerase-binding region. RAP30/74 or recombinant RAP30 suppresses nonspecific binding of RNA polymerase II to DNA and is required for RNA polymerase II to assemble stably into a preinitiation complex containing promoter DNA and the general factors TFIID, TFIIA and TFIIB; both RAP30 and RAP74 are physical components of the preinitiation complex. A complementary DNA encoding human RAP30 has been isolated, and here we report the isolation of a cDNA encoding human RAP74. RAP30 and RAP74 produced in Escherichia coli can be used in place of natural human RAP30/74 to direct accurate transcription initiation by RNA polymerase II in vitro.
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PMID:A cDNA encoding RAP74, a general initiation factor for transcription by RNA polymerase II. 173 84

We have investigated conditions that allow multiple rounds of transcription initiation from the adenovirus major late promoter in an in vitro system derived from HeLa cell nuclear extracts. Templates containing guanine-free cassettes provided a direct assay for discriminating between reinitiated transcripts and transcripts generated by a first-round of transcription initiations. When reactions were reconstituted with the previously characterized class II transcription factors (TFIIA, TFIIB, TFIID, TFIIE/F), transcription by human RNA polymerase II from the adenovirus major late promoter was essentially restricted to a single round of initiations. Reinitiations at previously transcribed major late templates required an additional activity, designated reinitiation transcription factor (RTF). The RTF activity could be separated from the required transcription initiation factors. Semipurified human RTF also promoted transcription reinitiations at minimal promoters derived from the human c-myc, histone H4, and heat shock 70-kDa protein genes, indicating that the same reinitiation factor may be utilized by many, if not all, genes. The possible role of RTF in regulating the transcription rate of various class II genes is discussed.
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PMID:Transcription factor requirement for multiple rounds of initiation by human RNA polymerase II. 196 36

We have subdivided the components of the basic RNA polymerase II machinery from Drosophila embryos into three fractions and RNA polymerase II. The RNA polymerase II was 90% homogeneous and possessed the IIa form of the largest subunit. By substitution of these factors with their mammalian homologues in reconstituted transcription reactions, we have determined that the three Drosophila fractions contain transcription factor (TF)IIB, TFIIE/F, and TFIID. In addition, the fraction with TFIID contains another essential activity, which we have tentatively designated as TFIIZ. There was no apparent requirement for TFIIA. The reconstituted transcription factors accurately transcribe both Drosophila and mammalian genes. This fractionated system should serve as a source of general transcription factors for the study of RNA polymerase II transcription in Drosophila as well as other eukaryotes.
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PMID:Fractionation of the general RNA polymerase II transcription factors from Drosophila embryos. 225 21

We have identified and partially characterized another human general transcription factor, TFIIG. Using a reconstituted in vitro system comprised of purified RNA polymerase II, TFIIB, TFIID, TFIIE, and TFIIF, we found that TFIIG was essential for specific initiation from all class II genes tested. In this system TFIIA could partially replace TFIIG; however, even at saturating concentrations of TFIIA, addition of TFIIG further stimulated transcription. Since the chromatographic properties of TFIIG differed significantly from those of TFIIA, we concluded that TFIIA and TFIIG are distinct but functionally related transcription factors. Heparin challenge assays showed that TFIIG is required for the assembly of a functional preinitiation complex. However, it must act after template commitment by TFIID, since this step did not require, and was unaffected by, either TFIIG or TFIIA.
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PMID:Factors involved in specific transcription by mammalian RNA polymerase II: identification of general transcription factor TFIIG. 225 Dec 57

We have investigated the earliest stages of assembly of an RNA polymerase II transcription complex. General transcription factors from HeLa cells were partially purified and assayed using the adenovirus-2 major late promoter. Preincubation of either all the transcription factors (TF) with the DNA or only the subset consisting of TFIIA, TFIID, and DNA overcame the 15-20 min lag normally observed. The kinetics demonstrate that TFIIA first interacts with the template over a 5 min. period, and then TFIID interacts with the IIA:DNA complex over a 2 min. period. The remainder of the necessary transcription factors then interact with the IIA:IID:DNA complex. There are apparently interactions between IIA and IID, as a pre-incubation of these factors (without DNA) overcomes the lag period. Both IIA:DNA and IIA:DNA:IID interactions are temperature sensitive, resulting in slower kinetics at 0 degree C. Thus, the kinetics of transcription involve activation processes in addition to DNA binding.
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PMID:Early events of RNA polymerase II transcription initiation. 231 95

Eucaryotic transcription initiation by RNA polymerase II involves protein:DNA interactions during the formation of a transcription complex. In addition to RNA polymerase II there are at least five other general transcription factors necessary for initiation with the adenovirus major late promoter. One of these, TFIIA, is involved in the earliest events during transcription complex assembly. We have purified TFIIA from wheat germ and characterized it in an in vitro transcription system. Wheat TFIIA is a single polypeptide of Mr approximately 35 kd which functionally replaces human (HeLa) TFIIA to form a wheat/HeLa transcription system. [This polypeptide can be eluted from a SDS-polyacrylamide gel, refolded to a native conformation, and will function as wheat TFIIA in the heterologous system.] The heterologous system requires a lower optimal incubation temperature than the HeLa system. Biochemical characterization, using the adenovirus major late promoter, indicates that transcription reaction parameters for both wheat and HeLa TFIIA are similar but the kinetics of transcription for both TFIIAs are somewhat dissimilar. A plant viral promoter, the cauliflower mosaic virus 35S promoter, accurately and efficiently directs in vitro transcription in both the wheat/HeLa and HeLa systems with identical transcription kinetics. We conclude that TFIIA function has been conserved during evolution.
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PMID:Transcription factor IIA of wheat and human function similarly with plant and animal viral promoters. 236 10

Transcription by RNA polymerase II occurs after formation of a transcription complex. This complex is assembled in stages by the interaction of transcription factors with the template and/or with each other. We report on the ability of six drugs to inhibit the assembly of the RNA polymerase II transcription complex. Assembly of the complex on the adenovirus major late promoter requires several transcription factors. The normal assembly process requires that the DNA first interact with TFIIA, then with TFIID, and finally with at least four additional transcription factors (one of which is RNA polymerase II). We observed that streptolydigin (10 micrograms/ml) inhibits association of ILA and IID, and at higher concentrations (100 micrograms/ml) inhibits that IIA/IID complex from binding to DNA. Streptovaricin (100 micrograms/ml) appears to inhibit the IIA/IID interaction with DNA and prevents reinitiation (at 500 micrograms/ml). Adriamycin (1 microgram/ml) inhibits the interaction of TFIID with the IIA/DNA complex and inhibits an additional event immediately prior to, or during, elongation. Daunorubicin may be an elongation inhibitor. Heparin at 10 micrograms/ml inhibits further assembly after the IIA/IID/DNA complex has formed, and at 100 micrograms/ml also inhibits a late event in the assembly process and blocks reinitiation. Rifamycin AF/013 (100 micrograms/ml) inhibits the early events necessary to form the IIA/IID/DNA complex and (at 10 micrograms/ml) an assembly event following formation of the IIA/IID/DNA complex. Therefore, these compounds should be useful as probes for further examination of the assembly process.
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PMID:Drug inhibitors of RNA polymerase II transcription. 257 59


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