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 rpoS gene encodes the second principal sigma factor of RNA polymerase in stationary-phase cells in Escherichia coli. We examined the transcription of Pseudomonas aeruginosa rpoS as to the growth of cells. The results of quantitative S1 nuclease mapping of rpoS and rpoD, encoding the principal sigma factor, indicated that the transcription of rpoS is induced in stationary-phase cells, whereas that of rpoD is induced in exponential-phase cells. By high-resolution S1 nuclease mapping, the 5'- and 3'-ends of rpoS mRNA were determined. The results indicated that rpoS is transcribed as a monocistronic mRNA. The sequence preceding the 5' end of rpoS mRNA showed poor homology to the consensus sequences of the previously known promoters. P. aeruginosa rpoS was not transcribed in E. coli. By in vitro transcription assaying, P. aeruginosa rpoS was shown to be transcribed by the RNA polymerase fraction containing the principal sigma (sigma 70)-RNA polymerase of P. aeruginosa.
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PMID:Transcription of the principal sigma-factor genes, rpoD and rpoS, in Pseudomonas aeruginosa is controlled according to the growth phase. 753 6

The nucleotide (nt) sequence of the bpdC1C2BADE genes which encode the first three enzymes in the biphenyl (BP) degradation pathway of Gram+ Rhodococcus sp. M5 (formerly Arthrobacter M5) was determined. Except for the ferredoxin component (BpdB) of the initial BP dioxygenase, the predicted amino acid (aa) sequences of the remaining proteins are found to be more closely related to the counterpart proteins (TodC1C2BADE) present in the toluene-degrader, Pseudomonas putida F1, than those of three BP-degrading pseudomonads. The cloned bpd genes were verified by their expression in the Escherichia coli T7 RNA polymerase/promoter system. In E. coli, BpdA was able to complement TodC1C2B in indigo biosynthesis, although the M5 native or cloned BP dioxygenase does not carry out this reaction.
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PMID:Sequence and expression of the bpdC1C2BADE genes involved in the initial steps of biphenyl/chlorobiphenyl degradation by Rhodococcus sp. M5. 759 Feb 99

hrpL of Erwinia amylovora Ea321 encodes a 21.7-kDa regulatory protein, similar to members of the ECF (extra cytoplasmic functions) subfamily of eubacterial RNA polymerase sigma factors. hrpL is a single-gene operon in complementation group VI of the E. amylovora hrp gene cluster. Its product is required by Ea321 to elicit the hypersensitive response (HR) and to cause disease. HrpL controls the expression of five independent hrp loci, including hrpN, which encodes harpin, a proteinaceous elicitor of the HR. hrpL is environmentally regulated, and its expression is affected by hrpS, another regulatory gene of the hrp gene cluster of E. amylovora. pCPP1078, a multicopy plasmid carrying hrpL, is able to restore HR-eliciting ability to hrpS mutants. A conserved motif was identified upstream of the hrpI and hrpN operons, which are transcriptionally regulated by hrpL. This conserved motif shares a high degree of similarity with other biochemically defined or putative ECF-dependent promoter sequences, including sequences upstream of Streptomyces coelicolor dagA P2, Pseudomonas aeruginosa algD, Pseudomonas syringae pv. syringae 61 hrpZ, and P. syringae pv. tomato avrD. In spite of the similarity between the hrpL genes of E. amylovora and P. syringae 61, no functional cross-complementation was observed.
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PMID:hrpL activates Erwinia amylovora hrp gene transcription and is a member of the ECF subfamily of sigma factors. 759 86

In the presence of toluene and xylenes, the sigma 54-dependent Ps promoter of the TOL (toluene biodegradation) plasmid pWW0 of Pseudomonas putida is activated at a distance by the XylR protein, of the NtrC family of transcriptional regulators. Since contacts between XylR bound to upstream activating sites and the RNA polymerase require the looping out of the intervening DNA segment, the intrinsic curvature, the bendability of the corresponding sequence, and the spatial effects of protein-induced DNA bending have an influence on promoter activity. Unlike other sigma 54-dependent promoters, Ps does not require the structural aid of the integration host factor to assemble a specific promoter geometry required for transcriptional initiation. In vivo analysis of transcriptional activity in various genetic backgrounds suggests, instead, that the looping out of intervening DNA sequences in Ps would result from the exacerbation of a preexisting static bend within the region, assisted by the histone-like protein HU.
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PMID:The sigma 54-dependent promoter Ps of the TOL plasmid of Pseudomonas putida requires HU for transcriptional activation in vivo by XylR. 760 41

Type 4 pili are essential for virulence in Neisseria gonorrhoeae. The gonococcal pilin subunit is encoded by pilE, upstream of which three putative promoter sequences (P1, P2, and P3) have been identified. P1 and P2 are sigma 70-like promoters and are functional when a PpiE::cat transcriptional fusion is expressed in Escherichia coli DH5 alpha. P3 is sigma 54 dependent and overlaps the P1 sequence. Site-directed mutagenesis of the pilE promoters followed by transcriptional analysis in E. coli indicated that in the absence of an appropriate activator protein, binding of RNA polymerase-sigma 54 to P3 inhibits transcription from P1 on the order of 30-fold. Transcription from P3 was undetectable in E. coli. However, PilR-dependent, P3-associated expression was detected in Pseudomonas aeruginosa PAK containing a PpilE::cat fusion, with P3 the only intact promoter. A similar analysis was performed on gonococcal reporter strains containing wild-type and mutated PpilE::cat cassettes recombined into the chromosome. In such piliated gonococcal recombinants cultured in vitro, P1 was responsible for cat expression and almost certainly for transcription of pilE. Transcription from P2 and P3 was not detectable under these conditions. Inhibition of transcription from P1 by sigma 54 binding to P3 was not apparent in N. gonorrhoeae MS11-A, suggesting that sigma 54 was either absent or unable to bind to P3 in these cells.
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PMID:The pilE gene of Neisseria gonorrhoeae MS11 is transcribed from a sigma 70 promoter during growth in vitro. 760 44

In the presence of m-xylene, the Pu promoter of the TOL plasmid of Pseudomonas putida is activated by the prokaryotic enhancer-binding protein XylR. The intervening DNA segment between the upstream activating sequences (UASs) and those for RNA polymerase binding contains an integration host factor (IHF) attachment site that is required for full transcriptional activity. In the absence of IHF, the Pu promoter can be cross-activated by other members of the sigma 54-dependent family of regulatory proteins. Such illegitimate activation does not require the binding of the heterologous regulators to DNA and it is suppressed by bent DNA structures, either static or protein induced, between the promoter core elements (UAS and RNA polymerase recognition sequence). The role of IHF in some sigma 54 promoters is, therefore, not only a structural aid for assembling a correct promoter geometry but also that of an active suppressor (restrictor) of promiscuous activation by heterologous regulators for increased promoter specificity.
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PMID:Integration host factor suppresses promiscuous activation of the sigma 54-dependent promoter Pu of Pseudomonas putida. 763 81

In a mucB (algN) genetic background, insertion of an omega element approximately 200 bp downstream of glpD, encoding sn-glycerol-3-phosphate dehydrogenase from Pseudomonas aeruginosa, had an adverse effect on alginate biosynthesis from various carbon sources. The insertion inactivated glpM, a gene encoding a 12,040-M(r) hydrophobic protein containing 109 amino acids. This protein, which was expressed in a T7 RNA polymerase expression system, appears to be a cytoplasmic membrane protein.
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PMID:Identification of Pseudomonas aeruginosa glpM, whose gene product is required for efficient alginate biosynthesis from various carbon sources. 764 8

Chronic infection by alginate-producing (mucoid) Pseudomonas aeruginosa is the leading cause of mortality among cystic fibrosis (CF) patients. During the course of sustained infection, the production of an alginate capsule protects the bacteria and allows them to persist in the CF lung. One of the key regulators of alginate synthesis is the algT (algU) gene encoding a putative alternative sigma factor (sigma E). AlgT was hyperproduced and purified from Escherichia coli. The N-terminal sequence of the purified protein matched perfectly with that predicted from the DNA sequence. The purified protein, in the presence of E. coli RNA polymerase core enzyme, was able to initiate transcription of an algT promoter. Deletion of the -35 region of this promoter abolished this activity in vitro as well as in vivo. These data indicate that the algT gene encodes a sigma factor that is autoregulatory.
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PMID:The algT (algU) gene of Pseudomonas aeruginosa, a key regulator involved in alginate biosynthesis, encodes an alternative sigma factor (sigma E). 764 17

The genetic organization of the gene cluster containing pilA, the structural gene for type IV pilin of Pseudomonas aeruginosa, as well as the accessory genes pilB, pilC, and pilD, has been studied. DNA sequences capable of initiating transcription when fused to a promoterless lacZ gene have been identified in the pilA-pilB and pilB-pilC intergenic regions. Unlike pilA, which requires rpoN (encoding the sigma 54 subunit of RNA polymerase) and products of two regulatory genes, pilS and pilR, expression of pilB, pilC, or pilD did not depend on any of these transcriptional regulators. Moreover, transcription of pilA from the tac promoter in an rpoN mutant background resulted in piliated bacteria, suggesting that the RpoN-based regulatory network is specific for pilA and does not control expression of any other genes necessary for formation of pili. Insertion of the omega fragment containing strong transcriptional terminators into pilB, pilC, and pilD failed to have a polar effect on expression of downstream genes, as determined by the ability of each cloned gene to complement, in trans, the corresponding insertionally inactivated chromosomal copy. Insertions into pilC, however, resulted in decreased synthesis of PilD as determined by quantitation of PilD enzymatic activity in processing prepilin in vitro and by immunoassay. This finding suggests that PilD may require PilC for its optimal stability or correct membrane localization.
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PMID:Genetic and functional characterization of the gene cluster specifying expression of Pseudomonas aeruginosa pili. 768 Oct 46

In Pseudomonas putida carrying the CAM plasmid, the operon (camDCAB) encoding enzymes involved in the degradation pathway of D-camphor is negatively regulated by the CamR protein, and camR is autorepressed. S1 nuclease mapping revealed that camDCAB and camR were divergently transcribed from overlapping promoters, the transcription start sites were separated by 11 bp, and transcriptions of the cam operon (camDCAB) and camR increased about 10- and 4-fold, respectively, immediately after addition of camphor. The transcriptions of camDCAB and camR were negatively regulated through the interaction of the CamR protein with the one operator located in the overlapping promoter region. In vitro transcription experiments were performed to characterize the regulation of cam genes. The camR promoter was initiated by P. putida RNA polymerase containing sigma 70, but transcription from the camDCAB promoter by sigma 70 holoenzyme was not observed. The purified CamR protein repressed in vitro transcription from the camR promoter. This repression was suppressed by camphor. The RNA polymerase binding region of the camR promoter was identified by using DNase I footprinting. In addition, footprinting studies revealed that the CamR protein and RNA polymerase coexisted on the promoter region in a joint nonproductive complex.
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PMID:Transcription of the cam operon and camR genes in Pseudomonas putida PpG1. 769 53


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