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)

Promoters of genes for bacteriophage lambda and for Escherichia coli ribosomal RNA (rrnB), elongation factor Tu (tufB), ribosomal proteins L11 (rplK), L1 (rplA), L10 (rplJ), and L7/L12 (rplL), and RNA polymerase subunits beta (rpoB) and beta' (rpoC) were studied by use of two types of filter binding assays which measured E. coli RNA polymerase binding and initiation of transcription on restriction fragments of lambda rifd 18 DNA. The DNA fragments selectively retained on filters were eluted, concentrated, and analyzed by gel electrophoresis. The binding characteristics of these promotor fragments were qualitatively determined by varying the RNA polymerase, salt, and glycerol concentrations in the polymerase binding assay with HaeIII fragments of lambda rifd 18 DNA. The approximate map locations of these small HaeIII fragments were determined by HaeIII digestion of the larger, previously mapped EcoRI, HindIII, and SmaI restriction fragments of the phage DNA. The base compositions proximal to the 5' ends of mRNA's from promoters on these DNA fragments were elucidated by the polymerase initiation assay, in which the addition of various combinations of nucleoside triphosphates to the reaction allowed RNA polymerase to form high-salt-resistant initiation complexes with some of the known SmaI + EcoRI, EcoRI + HindIII, or HaeIII restriction fragments of lambda rifd 18 DNA. The data obtained by this technique are consistent with the map positions and 5' mRNA base sequences of the known lambda promotors p'R, po, pR and pL. In the main focus of this work, we have determined the approximate map locations and 5' mRNA base compositions of several promoters for known E. coli genes including rrnB, tufB, rplK,A, and rplJ,L. No promoter was detected between rplL and the rpoB,C genes. Thus our data are consistent with the conclusion of Yamamoto and Nomura (1978) that the beta and beta' mRNA is probably cotranscribed from the promoter for rplJ,L. Finally, the approximate map positions and the NTP combinations which initiated transcription of several unknown lambda and E. coli in vitro promoters are reported. The methods reported should prove useful for studying the characteristics of promoters on other cloned DNA regions.
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PMID:Escherichia coli RNA polymerase binding and initiation of transcription on fragments of lambda rifd 18 DNA containing promoters for lambda genes and for rrnB, tufB, rplC,A, rplJ,L, and rpoB,C genes. 15 6

The DNA of the transducing phage lambdarifd18 contains, among others, the genes for the ribosomal proteins L11, L1, L10, and L12 and the beta and beta' subunits of RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6). In a coupled in vitro protein-synthesis system, lambdarifd18 DNA directs the synthesis of about four to five molecules of L12 per molecule of L10. This is consistent with the finding that there are four copies of L12 per ribosome. The ratio of L12/L10 was also examined from an EcoRI fragment of lambdarifd18 that contains the L10 gene and about 50% of the L12 gene. A significantly lower ratio of truncated L12/L10 was observed compared to the intact phage. The binding of RNA polymerase to various lambdarifd18 DNA restriction fragments was used to locate possible promoter sites. These binding experiments suggest that the beta and beta' subunits of RNA polymerase are cotranscribed with at least ribosomal protein L12 and, also, that there may be an additional promoter site for the L12 gene within the structural gene for L10.
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PMID:In vitro regulation of DNA-dependent synthesis of Escherichia coli ribosomal protein L12. 28 12

The lambdarifd18 transducing phage carries genes for RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase; EC 2.7.7.6) subunits beta and beta' (rpoB,C) and genes for four ribosomal proteins (rplK for L11, rplA for LI, rplJ for L10, and rplL for L7/L12). DNA segments of various sizes, which cover the rifd allele of the rpoB gene, were cloned into lambda vector phages. The hybrid phages were then analyzed for their ability to express the rpoB gene and neighboring ribosomal protein genes in ultraviolet-irradiated lambda-lysogenic and nonlysogenic bacterial hosts. The results show that the rpoB gene is cotranscribed with two neighboring ribosomal protein genes and that in the rpoB,C transcription unit is: promoter, rp1J, rp1L, rpoB, and rpoC.
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PMID:Contranscription of genes for RNA polymerase subunits beta and beta' with genes for ribosomal proteins in Escherichia coli. 35 3

The 3072-nucleotide-long sequence of a segment from the 88-min region of the Escherichia coli chromosome has been determined. The sequence covers the genes for ribosomal proteins L11 (rplK), LI (rplA), L10 (rplJ), and L7/L12 ((rplL), and the 5' end of the gene for the beta subunit of RNA polymerase (rpoB), along with the presumed regulatory regions for these genes. The probable locations of the promoter for the first two genes (the L11 operon) and the promoter for the latter three genes (the proximal part of the beta operon) have been identified. We have also found that the four ribosomal protein genes preferentially use codons that are recognized efficiently by the most abundant tRNA species. These and other features of the sequence results are discussed in relation to available information obtained from both in vitro and in vivo experiments on the expression of these ribosomal and RNA polymerase subunit genes.
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PMID:Nucleotide sequence of the ribosomal protein gene cluster adjacent to the gene for RNA polymerase subunit beta in Escherichia coli. 37 81

Fragments of lambda drifd 18 DNA with different end-points within the set of structural genes of ribosomal proteins L11 (RPLK), Li (rplA), L10 (rplJ) and L12 (rplL) as well as the beta (rpoB) ANd beta' (rpoC) subunits of RNA polymerase have been cloned on plasmids. These plasmids were transformed in host cells which were mutant for each of the genes, enabling expression of both wild-type (plasmid-borne) and mutant (chromosomal) genes to be differentiated. On the basis of these results we propose the following genetic structure for the region: rplK and rplA are in one operon; rplL, rpoB and rpoC are in a second. Our data suggest the possibility that rplJ is by itself in an operon situated between the other two.
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PMID:Expression of Escherichia coli ribosomal protein and RNA polymerase genes cloned on plasmids. 38 41

A 5789-nucleotide-long EcoRI fragment from the genome of Thermotoga maritima, identified by cross-hybridization to L11, L1, L10, and L12 ribosomal protein gene sequences from Escherichia coli, was cloned and sequenced. The fragment encodes five tRNAs (tRNA(met1), anticodon complementary to AUG; tRNA(met2), AUG; tRNA(thr), ACA; tRNA(tyr), UAC; tRNA(trp), UGG), the transcription termination-antitermination factor nusG, the four 50 S subunit ribosomal proteins L11, L1, L10, and L12, and the amino-terminal portion of the RNA polymerase beta subunit protein. The five tRNA genes, the nusG gene, and the L11, L1, L10, and L12 ribosomal protein genes form a complex transcription unit. Transcripts appear to be initiated from an upstream promoter, P1, located in front of the tRNA(met1) gene and from three internal promoters: P2 is located immediately in front of the tRNA(met2) gene; PL10 is near the beginning of the L1-L10 intergenic space, and PL12 is at the end of the L10 gene sequence. The tRNA sequences are excised from the leader regions of the P1- and P2-initiated transcripts. Three putative but potentially important regulatory sequences were identified within this operon: an L1 translational control site, a transcription attenuator, and a strong rho-independent terminator. The strong terminator located distal to the L12 gene overlaps a fifth promoter, P beta, which is used to initiate transcripts of the downstream RNA polymerase beta subunit gene. The T. maritima NusG protein exhibits 43% amino acid sequence identity when aligned to the E. coli protein; the alignment is interrupted by a large 171-amino acid-long insertion into the T. maritima protein after codon 45.
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PMID:The organization and expression of essential transcription translation component genes in the extremely thermophilic eubacterium Thermotoga maritima. 142 27

The relationship between global RNA transcription capacity and transcript initiation, attenuation, and stability in the rplKAJLrpoBC operon of Escherichia coli has been examined. The rplKAJLrpoBC operon encodes in order the four large ribosome subunit proteins, L11, L1, L10, and L12, and the two large beta and beta' subunits of RNA polymerase. Operon transcripts are initiated at two promoters, PL11 and PL10. The L12-beta intergenic space contains a transcription attenuator which, during balanced growth, terminates about 80% of the transcripts exiting the L12 gene; the remaining transcripts read through into the beta and beta' encoding genes. The capacity for global transcription initiation was modulated using a strain carrying a temperature-sensitive, initiation-defective mutation in rpoC. Following a shift to 39 degrees C, the global transcription initiation capacity was reduced to about one-half the level at 30 degrees C. This partial restriction resulted in a decrease in the stability of distal beta mRNA, whereas the stability of proximal L11-L1 and L10-L12 mRNA was not changed. Measurements of the synthesis rates of L11-L1, L10-L12, and beta mRNAs relative to total RNA synthesis indicated that this operon was selectively transcribed when the initiation capacity of RNA polymerase was limited. The synthesis rates of L11-L1 and L10-L12 mRNA increased about 2-fold, whereas the synthesis rate of beta mRNA increased nearly 5-fold. The relative transcription of other ribosome component genes and the alpha subunit gene exhibited only a modest increase during the partial restriction. Protection from S1 nuclease was used to demonstrate that the preferential transcription within the operon of beta mRNA was the consequence of active regulation of termination-antitermination at the attenuator structure in the L12-beta intergenic space. These results demonstrate that global transcription capacity may be an important parameter in determining both initiation and attenuation of transcription of the rplKAJLrpoBC ribosomal protein-RNA polymerase operon.
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PMID:RNA polymerase activity may regulate transcription initiation and attenuation in the rplKAJLrpoBC operon in Escherichia coli. 198 49

The E. coli genes rplKAJL specifying ribosomal proteins L11, L1, L10, L7/L12 are co-transcribed with the genes rpoBC encoding the beta- and beta'-subunits of RNA polymerase, but are separated by the site of attenuation. The efficiency of attenuation within rplKAJL-rpoBC operon was determined as a ratio of rplKAJL transcription frequency to the same of rpoBC genes. The efficiency of attenuation was found to be a growth-rate dependent parameter of E. coli cells. At growth rate 1.2 doublings per hour the attenuation is rare and simultaneously increases with the increase in the growth rate (at mu = 1.2 doublings per hour the efficiency of attenuation is 4). Rifampicin (10-30 micrograms/ml) inhibits the transcription of both rplKAJL and rpoBC genes in fast growing cells but paradoxically stimulates their transcription in slowly growing cells. The stimulatory effect of rifampicin on rplKAJL genes transcription is supposed to be based on its ability to repress the ppGpp synthesis. The possible role of ppGpp in the regulation of transcription attenuation in rplKAJL-rpoBC operon is discussed.
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PMID:[Transcription of ribosomal protein genes rplKAJL and RNA-polymerase genes rpoBC in Escherichia coli cells: metabolic regulation of attenuation and the effect of rifampicin]. 243 Jan 72

Transcripts from the rplKAJL-rpoBC ribosomal protein-RNA polymerase gene cluster have been quantified and their ends mapped using RNA-DNA hybridization, sucrose density-gradient sedimentation, Northern hybridization and S1 nuclease protection. The results indicate that the most abundant transcript is the 2600 nucleotide tetracistronic L11-L1-L10-L12 mRNA initiated at the upstream major PL11 promoter and terminated at the transcription attenuator in the L12-beta intergenic space. Somewhat less abundant 1300 nucleotide L11-L1 and L10-L12 bicistronic transcripts were observed. The 3' ends of the L11-L1 transcripts were heterogeneous; most of the ends were localized to three sites within a 110 base-pair region in the L1-L10 intergenic space. This intergenic space encodes also the major PL10 promoter and the mRNA binding site for the L10 translational control protein. Two 5' ends were observed for L10-L12 bicistronic mRNA, one at the PL10 promoter and the other 150 nucleotides further downstream in a region in which promoter activity has not been detected. It is suggested that this second downstream 5' end is generated by processing of the transcripts initiated at the major PL10 promoter. No transcript initiation in the L10-L12 intergenic space was detected. About 80% of the transcripts reading through the L12 gene were terminated in the vicinity of the transcription attenuator that is responsible for the reduction in the expression of the downstream RNA polymerase genes. Transcripts reading through the attenuator were partially processed by RNase III within a potential hairpin structure in the RNA transcript. Processing appears to produce 3' and 5' transcript end sites separated by about ten nucleotides. No other major 5' ends were observed in the L12-beta intergenic space. These results indicate that the two major promoters, PL11 and PL10, are both utilized to drive the interrelated transcriptional expression of this ribosomal protein-RNA polymerase gene cluster.
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PMID:Transcription products from the rplKAJL-rpoBC gene cluster. 244 6

The secondary structure of the autoregulatory mRNA binding site of Escherichia coli ribosomal protein L1 has been studied using enzymatic methods. The control region of the E. coli L11 operon was cloned into a vector under control of the Salmonella phage SP6 promoter, and RNA transcribed using SP6 RNA polymerase. The secondary structure of this RNA was probed using structure-specific nucleases, and by comparison of the data with computer predictions of RNA folding, secondary structural features were deduced. The proposed model is consistent with elements of some previously proposed models, but differs in other features. Finally, secondary structure information was obtained from two mutant mRNAs and the structural features correlated with observed phenotypes of the mutants.
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PMID:Secondary structure of the autoregulatory mRNA binding site of ribosomal protein L1. 244 90


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