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)

In vitro transcription assays have been used to study the rate of ribonucleic acid (RNA) synthesis from the Escherichia coli lactose promotor mutant lacL8UV5 contained on a 203-bp (base pair) restriction fragment. The half-life of long (63-base) RNA production from heparin-resistant RNA polymerase-promotor complexes was found to be related to the amount of oligonucleotides released during the initiation process (abortive initiation). Studies indicate that once a ternary complex between the promoter, RNA polymerase, and a newly synthesized RNA seven and nine nucleotides long is formed, abortive initiation is reduced and the rate of synthesis of long RNAs is increased. The promoter for the left inverted repeat of the transposable element Tn5 was also examined. It was observed to have a much slower rate of production of long RNAs, and it released oligonucleotides 4 times as often as the lactose promoter. The correlation between the amount of abortive initiation and the half-time of long RNA production is discussed.
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PMID:Abortive initiation and long ribonucleic acid synthesis. 616 80

The ability of indole derivatives to facilitate RNA polymerase transcription of the L-arabinose operon in Escherichia coli was shown to require the catabolite activator protein (CAP) as well as the araC gene product. Adenosine 3',5'-monophosphate (cAMP) was not obligatory for araBAD transcription when the cells were grown in the presence of 1 mM indole-3-acetic acid or in the presence of indole-3-acetamide, indole-3-propionic acid, indole-3-butyric acid, or 5-hydroxyindole-3-acetic acid. However, these indole derivatives were unable to circumvent the cAMP requirement for the induction of the lactose and the maltose operons. Catabolic repression occurred when glucose was added to cells grown in the presence of L-arabinose and 1 mM indoleacetic acid or 1 mM cAMP. This effect was reversed at higher concentrations of indoleacetic acid or cAMP. The induction and the catabolite repression phenomena were quantitated by measuring the differential rate of synthesis of L-arabinose isomerase (the araA gene product). These results indicated that indole metabolites from various living systems may regulate gene expression and may be involved in "metabolite gene regulation."
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PMID:Metabolite gene regulation of the L-arabinose operon in Escherichia coli with indoleacetic acid and other indole derivatives. 624 2

The cyclic AMP receptor protein (CRP) stimulates transcription of the lactose operon by binding to the lac promoter. I have identified those 5-positions of thymines in the promoter that lie close to bound CRP. Although ultraviolet irradiation of DNA with 5-bromouracil substituted in place of thymine normally cleaves the DNA at the bromouracils, a protein bound to the DNA can perturb these cleavages at those locations at which the protein lies close to the bromine. The contacts inferred from this photochemical probe and the results of nucleolytic attack of this complex by exonuclease III support a model where the cyclic AMP receptor protein binds to the promoter making symmetrical contacts with one face of the double helix and then stimulates transcription through contacts with RNA polymerase.
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PMID:Interaction of the cAMP receptor protein with the lac promoter. 625 23

The use of gel electrophoresis for quantitative studies of DNA-protein interactions is described. This rapid and simple technique involves separation of free DNA from DNA-protein complexes based on differences in their electrophoretic mobilities in polyacrylamide gels. Under favorable conditions both unbound DNA and DNA associated with protein can be quantified. This gel method is applied to the study of the E. coli lactose operon regulatory system. At ionic strengths in the physiological range, the catabolite activator protein (CAP) is shown to form a long-lived complex with the wild type lac promotor, but not with a CAP-insensitive mutant. Formation of a stable "open" or "melted-in" complex of RNA polymerase with the wild type promoter requires the participation of CAP and cyclic AMP. Further, it is demonstrated that even when pre-formed in the presence of CAP-cAMP, the polymerase-promoter open complex becomes unstable if CAP is then selectively removed.
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PMID:A gel electrophoresis method for quantifying the binding of proteins to specific DNA regions: application to components of the Escherichia coli lactose operon regulatory system. 626 71

Superhelical pBR 322 derivatives have been relaxed by eukaryotic topoisomerase I in the presence or in the absence of E. coli cyclic AMP receptor protein (CRP) and of cyclic AMP (cAMP). CRP alone, or cAMP alone do not affect the average linking number of the distribution of the relaxed topoisomers. Hence, they do not unwind the template. In the presence of cAMP, CRP induces a small unwinding. The extent of this unwinding is barely modified when the relaxation is carried out on a similar vector plasmid where the CRP binding site of the lac or of the gal operon has been inserted. Under these conditions, we checked that CRP occupies the lactose control site and that upon addition of RNA polymerase, the corresponding promoter is readily activated. These findings are difficult to reconcile with the proposal that activation of these promoters results from the binding of the CRP-cAMP complex to left-handed DNA sequences.
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PMID:Is DNA unwound by the cyclic AMP receptor protein? 627 15

Restriction fragments containing the region preceding the tryptophanase structural gene, tnaA, were used as templates for in vitro transcription experiments. A transcription initiation site was detected that was dependent on the catabolite gene activator protein (CAP) plus cyclic AMP (cAMP). The mRNA produced in vitro was fingerprinted, and the nucleotide at which transcription was initiated was localized to the vicinity of two guanine residues 316 and 318 base pairs upstream of tnaA. A region exhibiting extensive difold symmetry and homology to the CAP binding site adjacent to the lactose operon promoter exists approximately 60 base pairs preceding the site of transcription initiation. Two HinfI restriction sites are located in this region. Restriction enzyme cleavage at these sites was prevented when DNA containing the promoter region was preincubated with CAP and cAMP. RNA polymerase was incapable of protecting these sites against this cleavage. CAP and cAMP addition did not protect against cleavage at a DdeI restriction site located in the -20 region of the promoter. RNA polymerase did protect against DdeI cleavage but only in the presence of CAP and cAMP. Thus, transcription initiation at the tryptophanase promoter involves cAMP-dependent, CAP-facilitated binding of RNA polymerase to the DNA.
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PMID:Transcription initiation at the tryptophanase promoter of Escherichia coli K-12. 628 18

To assess the role of neighboring DNA sequences in gene regulation, poly(dA).poly(dT) and poly(dG).poly(dC) were cloned adjacent to promoters of the lactose control region. Recombinant plasmids were constructed which were suitable for large scale purification of restriction fragments containing these promoters, 95-base pair (bp) AluI fragments containing the lack operator and promoter for the lac wild type and for the catabolite gene activating the protein-independent mutant, lac UV5, were cloned into pBR322. Homopolymers of varying lengths were inserted into the -60 region of these promoters using recombinant DNA techniques. Six of the recombinant plasmids were chosen for detailed analysis: wild type (wt); wt-AT, containing 70 bp of poly(dA).poly(dT); wt-GC, containing 23 bp of poly(dG).poly(dC); UV5; UV5-AT, containing 70 bp of poly(dA).poly(dT) and finally UV5-GC, containing 43 bp of poly(dG).poly(dC). These plasmids were characterized by restriction mapping and DNA sequencing. The effects of the DNA homopolymers on the interaction of the Escherichia coli RNA polymerase with the promoters were studied using nitrocellulose filter binding. The results show that poly(dA).poly(dT) increases the level of RNA polymerase binding, whereas poly(dG).poly(dC) has no detectable effect.
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PMID:Effects of neighboring DNA homopolymers on the biochemical and physical properties of the Escherichia coli lactose promoter. I. Cloning and characterization studies. 629 Apr 87

We have synthesized microgram quantities of a functional eucaryotic mRNA by in vitro transcription. For this purpose, we constructed a plasmid in which the Escherichia coli lactose promoter was 5' to the vesicular stomatitis virus (VSV) G protein gene (Rose, J. K., and C. J. Gallione, 1981, J. Virol., 39:519-528). This DNA served as the template in an in vitro transcription reaction utilizing E. coli RNA polymerase. The RNA product was capped using the vaccinia guanylyltransferase. A typical preparation of the synthetic G mRNA was equivalent to the amount of G mRNA that can be isolated from approximately 10(8) VSV-infected cells. This synthetic mRNA was translated by a wheat germ extract in the presence of microsomes, producing a polypeptide that was indistinguishable from G protein in its size, antigenicity, degree of glycosylation, and its membrane insertion. This technique should aid in identifying features needed by proteins for insertion into membranes.
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PMID:Construction of a synthetic messenger RNA encoding a membrane protein. 634 80

Using the in vitro mixed transcription system (Kajitani, M. and Ishihama, A. (1983) Nucleic Acids Res. 11, 671-686), we determined the two parameters of the promoter strength, i.e., the rate of open complex formation between RNA polymerase and promoter, and the saturation level of the open complex formation at equilibrium, for the promoters of ribosomal RNA (rrnE), ribosomal protein S1 (rpsA) and recA protein (recA) operons from Escherichia coli. Taken together with the previous determinations for lactose (lac(UV5)), tryptophan (trp) and ribosomal protein L10 (rp1J) operons, these studies revealed that the relative promoter strengths with respect to the kinetic parameter are 200, 70, 50, 40, 30, 20 and 2% of the reference promoter lacP(UV5) for recAp, rp1Jp, rpsAp3, trpP, rpsAp1, rrnEp1 and rrnEp2, respectively, under our standard reaction conditions (50 mM NaCl and 37 degrees C); and those with respect to the thermodynamic parameter are 70, 35, 20, 10, 10, 10 and 5% the level of lacP(UV5) for rrnEp2, trpP, rpsAp3, rp1Jp, rpsAp1, rrnEp1 and recAp, respectively. The order of the promoter strength, however, changes with variation of the salt concentration or reaction temperature.
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PMID:Determination of the promoter strength in the mixed transcription system. II. Promoters of ribosomal RNA, ribosomal protein S1 and recA protein operons from Escherichia coli. 634 67

Using the in vitro mixed transcription system (Kajitani, M., and Ishihama, A. (1983) Nucleic Acids Res. 11, 671-686; Kajitani, M., and Ishihama, A. (1983) Nucleic Acids Res., 11, 3873-3889) we examined the effect of guanosine 3'-diphosphate, 5'-diphosphate (ppGpp), the chemical mediator of stringent control, on transcription of various Escherichia coli DNA fragments, each carrying a single specific promoter. We found that ppGpp inhibits transcription of stringently controlled genes, rrnE, rpsA, and rplJ, coding for ribosomal RNA, ribosomal protein S1 and L10, respectively, but not that of trp (tryptophan) and lacUV5 (lactose) genes. Among the multiple promoters of the rrnE and rpsA operons, the upstream promoters, rrnEp1 and rpsAp1, are subject to repression by ppGpp but the downstream promoters, rrnEp2 and rpsAp3, are insensitive. Taking these facts and the intrinsic strength of the respective promoters together, we suggest that the multiple promoters within the single and same operons play different physiological roles and are regulated by independent mechanisms. The inhibition by ppGpp takes place even after formation of open complexes, suggesting that the RNA polymerase bound to the sensitive promoters is accessible for interaction with ppGpp leading to rapid decay of the open complexes. During this study, we noticed that some promoters including recAp are activated in the presence of ppGpp, raising a possibility that ppGpp has dual effects on the promoter function.
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PMID:Promoter selectivity of Escherichia coli RNA polymerase. Differential stringent control of the multiple promoters from ribosomal RNA and protein operons. 636 18


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