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)

Transcription of SP82 and SP01 DNAs in vitro by Bacillus subtilis RNA polymerase yielded mostly large RNA species, with many in excess of 1,500 bases in length, whereas most of the RNAs synthesized in vivo early in infection were much smaller. Addition of an extract from uninfected B. subtilis to reaction mixtures containing RNAs synthesized in vitro generated additional discrete RNAs whose mobilities on polyacrylamide gels matched the mobilities of some of the smaller RNAs synthesized in vivo.
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PMID:Early RNAs in SP82- and SP01-infected Bacillus subtilis may be processed. 678 48

We have examined the effect of the delta subunit of the Bacillus subtilis RNA polymerase on the formation of closed, open, and stably initiated complexes with Hha I restriction fragments of phage SP82 DNA; the effect of delta on the transcription of these DNA fragments has also been investigated. In vitro, the holoenzyme (core-sigma-delta) bound to and transcribed the same regions of the phage genome that are transcribed in vivo early in infection. In the absence of the delta subunit, the polymerase (core-sigma) bound nonspecifically and transcribed regions of the genome other than those containing early phage genes. Addition of delta to preparations of core-sigma restored the pattern of binding and transcription observed with the holoenzyme. Similarly, delta-less preparations of two SP82-modified forms of polymerase (the enzyme isolated at 8 min after infection and the enzyme isolated 20 min after infection) bound nonspecifically and transcribed regions of the genome other than those containing "middle" and "late" genes. Addition of delta to these preparations resulted in patterns of binding and transcription expected for enzymes functioning a middle and late times of infection, respectively. Quantitation of polymerase-DNA complexes at various temperatures, NaCl concentrations, and polymerase-DNA ratios supported the conclusion that delta enhanced promoter selection.
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PMID:The role of the delta peptide of the Bacillus subtilis RNA polymerase in promoter selection. 678 69

Bacillus subtilis bacteriophage SP82 codes for several early RNAs that were shown previously to be cleaved by an RNase III-like enzyme called "Bs-RNase III." Cloning of DNA fragments that encode these RNA sequences downstream of a T7 RNA polymerase promoter allowed the synthesis of substrates that were used to test the cleavage specificity of Bs-RNase III, which was purified from a protease-deficient strain of B. subtilis. Single nucleotide changes at or near the cleavage site and deletions upstream and downstream of the cleavage site were constructed. The effects of these changes on the rate of Bs-RNase III cleavage were measured. The activity of Bs-RNase III and Escherichia coli RNase III on heterologous substrates was also tested. Although the local environment of the site of Bs-RNase III cleavage appears very similar to that of E. coli RNase III, there are important differences in their substrate specificity.
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PMID:Substrate specificity of an RNase III-like activity from Bacillus subtilis. 752 87

The ability of curved DNA upstream of the -35 region to affect the interaction of Escherichia coli RNA polymerase and promoter DNA was examined through the use of hybrid promoters. These promoters were constructed by substituting the curved DNA from two Bacillus subtilis bacteriophage SP82 promoters for the comparable DNA of the bacteriophage lambda promoters lambda pR and lambda pL. The SP82 promoters possessed intrinsic DNA curvature upstream of their -35 regions, as characterized by runs of adenines in phase with the helical repeat. In vitro, the relative affinities of purified sigma 70-RNA polymerase for the promoters were determined in a competition binding assay. Hybrid promoters derived from lambda pR that contained curved DNA were bound by E. coli RNA polymerase more efficiently than was the original lambda pR. Binding of E. coli RNA polymerase to these hybrid promoters was favored on superhelical DNA templates according to gel retardation analysis. Both the supercoiled and relaxed forms of the hybrid lambda pL series were better competitors for E. coli RNA polymerase binding than was the original lambda pL. The results of DNase I footprinting analysis provided evidence for the wrapping of the upstream curved DNA of the hybrid lambda pR promoters around the E. coli RNA polymerase in a tight, nucleosomal-like fashion. The tight wrapping of the upstream DNA around the polymerase may facilitate the subsequent steps of DNA untwisting and strand separation.
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PMID:Role of curved DNA in binding of Escherichia coli RNA polymerase to promoters. 759 19

20-Epi-1,25-dihydroxyvitamin D(3) (20-epi-1,25(OH)(2)D(3)) is a vitamin D analog that exhibits unique biologic properties. The mechanism(s) responsible for these activities remains unclear. Here we explore the ability of 20-epi-1,25(OH)(2)D(3) to induce calcemic responses in mice in vivo and identify a potential mechanism. Surprisingly, the levels of calcemia induced at 24 h after single injections of equivalent doses of 1,25(OH)(2)D(3) or 20-epi-1,25(OH)(2)D(3) were similar, suggesting that both compounds were equal in both potency and efficacy. This similarity was also observed at genes involved in calcium homeostasis including, S100g (calbindin D9K), Trpv6, Cldn2 (claudin 2), Trpv5, and Tnfsf11 (Rankl) as well as Cyp24a1. Despite this, the activities of the two compounds at 48 h were strikingly different. Thus, whereas the activity of 1,25-dihydroxyvitamin D(3) declined at this time point, the response to 20-epi-1,25(OH)(2)D(3) was increased. This unique profile was not due to an exaggerated induction of calcium regulating genes in the intestine, kidney, or bone but to a sustained action on these genes in the intestine. This conclusion was supported by studies using in vivo chromatin immunoprecipitation analysis, which revealed a prolonged presence of vitamin D receptor and RNA polymerase II at the Trpv6 and Cyp24a1 promoters and a sustained increase in histone 4 acetylation in these gene regions as well. We conclude that 20-epi-1,25(OH)(2)D(3) displays superagonist properties largely as a result of its duration of action in the intestine. This action is likely due to a decrease in the rate of intestinal-specific degradation of the ligand rather than to an increase in the functional stability of the vitamin D receptor.
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PMID:The enhanced hypercalcemic response to 20-epi-1,25-dihydroxyvitamin D3 results from a selective and prolonged induction of intestinal calcium-regulating genes. 1942 58


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