Base de dados : MEDLINE
Pesquisa : D12.776.260.527 [Categoria DeCS]
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[PMID]:28057466
[Au] Autor:Ihara K; Sato K; Hori H; Makino Y; Shigenobu S; Ando T; Isogai E; Yoneyama H
[Ad] Endereço:Laboratory of Animal Microbiology, Department of Microbial Biotechnology, Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba, Aoba-ku, Sendai 980-0845, Japan.
[Ti] Título:Expression of the alaE gene is positively regulated by the global regulator Lrp in response to intracellular accumulation of l-alanine in Escherichia coli.
[So] Source:J Biosci Bioeng;123(4):444-450, 2017 Apr.
[Is] ISSN:1347-4421
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:The alaE gene in Escherichia coli encodes an l-alanine exporter that catalyzes the active export of l-alanine using proton electrochemical potential. In our previous study, alaE expression was shown to increase in the presence of l-alanyl-l-alanine (Ala-Ala). In this study, the global regulator leucine-responsive regulatory protein (Lrp) was identified as an activator of the alaE gene. A promoter less ß-galactosidase gene was fused to an alaE upstream region (240 nucleotides). Cells that were lacZ-deficient and harbored this reporter plasmid showed significant induction of ß-galactosidase activity (approximately 17-fold) in the presence of 6 mM l-alanine, l-leucine, and Ala-Ala. However, a reporter plasmid possessing a smaller alaE upstream region (180 nucleotides) yielded transformants with strikingly low enzyme activity under the same conditions. In contrast, lrp-deficient cells showed almost no ß-galactosidase induction, indicating that Lrp positively regulates alaE expression. We next performed an electrophoretic mobility shift assay (EMSA) and a DNase I footprinting assay using purified hexahistidine-tagged Lrp (Lrp-His). Consequently, we found that Lrp-His binds to the alaE upstream region spanning nucleotide -161 to -83 with a physiologically relevant affinity (apparent K , 288.7 ± 83.8 nM). Furthermore, the binding affinity of Lrp-His toward its cis-element was increased by l-alanine and l-leucine, but not by Ala-Ala and d-alanine. Based on these results, we concluded that the gene expression of the alaE is regulated by Lrp in response to intracellular levels of l-alanine, which eventually leads to intracellular homeostasis of l-alanine concentrations.
[Mh] Termos MeSH primário: Alanina/metabolismo
Escherichia coli/genética
Escherichia coli/metabolismo
Regulação Bacteriana da Expressão Gênica
Proteína Reguladora de Resposta a Leucina/metabolismo
[Mh] Termos MeSH secundário: Alanina/farmacologia
Sistemas de Transporte de Aminoácidos Neutros/biossíntese
Sistemas de Transporte de Aminoácidos Neutros/genética
Sistemas de Transporte de Aminoácidos Neutros/metabolismo
Sequência de Bases
Pegada de DNA
Desoxirribonuclease I/metabolismo
Dipeptídeos/metabolismo
Dipeptídeos/farmacologia
Ensaio de Desvio de Mobilidade Eletroforética
Escherichia coli/efeitos dos fármacos
Proteínas de Escherichia coli/biossíntese
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos
Genes Reporter/genética
Leucina/metabolismo
Leucina/farmacologia
Proteína Reguladora de Resposta a Leucina/deficiência
Óperon/efeitos dos fármacos
Ligação Proteica/efeitos dos fármacos
Sequências Reguladoras de Ácido Nucleico/genética
Regulação para Cima/efeitos dos fármacos
beta-Galactosidase/genética
beta-Galactosidase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (AlaE protein, E coli); 0 (Amino Acid Transport Systems, Neutral); 0 (Dipeptides); 0 (Escherichia coli Proteins); 138791-20-5 (Leucine-Responsive Regulatory Protein); 2867-20-1 (alanylalanine); EC 3.1.21.1 (Deoxyribonuclease I); EC 3.2.1.23 (beta-Galactosidase); GMW67QNF9C (Leucine); OF5P57N2ZX (Alanine)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170502
[Lr] Data última revisão:
170502
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170107
[St] Status:MEDLINE


  2 / 216 MEDLINE  
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[PMID]:27206730
[Au] Autor:Unoarumhi Y; Blumenthal RM; Matson JS
[Ad] Endereço:Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
[Ti] Título:Evolution of a global regulator: Lrp in four orders of γ-Proteobacteria.
[So] Source:BMC Evol Biol;16(1):111, 2016 May 20.
[Is] ISSN:1471-2148
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Bacterial global regulators each regulate the expression of several hundred genes. In Escherichia coli, the top seven global regulators together control over half of all genes. Leucine-responsive regulatory protein (Lrp) is one of these top seven global regulators. Lrp orthologs are very widely distributed, among both Bacteria and Archaea. Surprisingly, even within the phylum γ-Proteobacteria (which includes E. coli), Lrp is a global regulator in some orders and a local regulator in others. This raises questions about the evolution of Lrp and, more broadly, of global regulators. RESULTS: We examined Lrp sequences from four bacterial orders of the γ-Proteobacteria using phylogenetic and Logo analyses. The orders studied were Enterobacteriales and Vibrionales, in which Lrp plays a global role in tested species; Pasteurellales, in which Lrp is a local regulator in the tested species; and Alteromonadales, an order closely related to the other three but in which Lrp has not yet been studied. For comparison, we analyzed the Lrp paralog AsnC, which in all tested cases is a local regulator. The Lrp and AsnC phylogenetic clusters each divided, as expected, into subclusters representing the Enterobacteriales, Vibrionales, and Pasteuralles. However the Alteromonadales did not yield coherent clusters for either Lrp or AsnC. Logo analysis revealed signatures associated with globally- vs. locally- acting Lrp orthologs, providing testable hypotheses for which portions of Lrp are responsible for a global vs. local role. These candidate regions include both ends of the Lrp polypeptide but not, interestingly, the highly-conserved helix-turn-helix motif responsible for DNA sequence specificity. CONCLUSIONS: Lrp and AsnC have conserved sequence signatures that allow their unambiguous annotation, at least in γ-Proteobacteria. Among Lrp orthologs, specific residues correlated with global vs. local regulatory roles, and can now be tested to determine which are functionally relevant and which simply reflect divergence. In the Alteromonadales, it appears that there are different subgroups of Lrp orthologs, one of which may act globally while the other may act locally. These results suggest experiments to improve our understanding of the evolution of bacterial global regulators.
[Mh] Termos MeSH primário: Proteínas de Bactérias/genética
Evolução Molecular
Gammaproteobacteria/genética
Regulação Bacteriana da Expressão Gênica
Proteína Reguladora de Resposta a Leucina/genética
[Mh] Termos MeSH secundário: Proteínas de Bactérias/química
Evolução Biológica
Escherichia coli/genética
Proteínas de Escherichia coli/química
Proteínas de Escherichia coli/genética
Proteína Reguladora de Resposta a Leucina/química
Dados de Sequência Molecular
Filogenia
Análise de Sequência de Proteína
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Escherichia coli Proteins); 138791-20-5 (Leucine-Responsive Regulatory Protein)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170901
[Lr] Data última revisão:
170901
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160522
[St] Status:MEDLINE
[do] DOI:10.1186/s12862-016-0685-1


  3 / 216 MEDLINE  
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[PMID]:27137887
[Au] Autor:Lee HJ; Gottesman S
[Ad] Endereço:Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
[Ti] Título:sRNA roles in regulating transcriptional regulators: Lrp and SoxS regulation by sRNAs.
[So] Source:Nucleic Acids Res;44(14):6907-23, 2016 Aug 19.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Post-transcriptional regulation of transcription factors contributes to regulatory circuits. We created translational reporter fusions for multiple central regulators in Escherichia coli and examined the effect of Hfq-dependent non-coding RNAs on these fusions. This approach yields an 'RNA landscape,' identifying Hfq-dependent sRNAs that regulate a given fusion. No significant sRNA regulation of crp or fnr was detected. hns was regulated only by DsrA, as previously reported. Lrp and SoxS were both found to be regulated post-transcriptionally. Lrp, ' L: eucine-responsive R: egulatory P: rotein,' regulates genes involved in amino acid biosynthesis and catabolism and other cellular functions. sRNAs DsrA, MicF and GcvB each independently downregulate the lrp translational fusion, confirming previous reports for MicF and GcvB. MicF and DsrA interact with an overlapping site early in the lrp ORF, while GcvB acts upstream at two independent sites in the long lrp leader. Surprisingly, GcvB was found to be responsible for significant downregulation of lrp after oxidative stress; MicF also contributed. SoxS, an activator of genes used to combat oxidative stress, is negatively regulated by sRNA MgrR. This study demonstrates that while not all global regulators are subject to sRNA regulation, post-transcriptional control by sRNAs allows multiple environmental signals to affect synthesis of the transcriptional regulator.
[Mh] Termos MeSH primário: Proteínas de Escherichia coli/genética
Escherichia coli/genética
Regulação Bacteriana da Expressão Gênica
Proteína Reguladora de Resposta a Leucina/genética
RNA Bacteriano/metabolismo
Transativadores/genética
Transcrição Genética
[Mh] Termos MeSH secundário: Regiões 5' não Traduzidas/genética
Sequência de Bases
Proteínas de Escherichia coli/metabolismo
Proteína Reguladora de Resposta a Leucina/metabolismo
Conformação de Ácido Nucleico
Ligação Proteica
Biossíntese de Proteínas
RNA Bacteriano/genética
RNA Mensageiro/genética
RNA Mensageiro/metabolismo
Transativadores/metabolismo
Fatores de Transcrição/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (5' Untranslated Regions); 0 (Escherichia coli Proteins); 0 (Lrp protein, E coli); 0 (RNA, Bacterial); 0 (RNA, Messenger); 0 (Trans-Activators); 0 (Transcription Factors); 137804-82-1 (SoxS protein, E coli); 138791-20-5 (Leucine-Responsive Regulatory Protein)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170605
[Lr] Data última revisão:
170605
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160504
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkw358


  4 / 216 MEDLINE  
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[PMID]:26843427
[Au] Autor:Ishihama A; Shimada T; Yamazaki Y
[Ad] Endereço:Micro-Nano Technology Research Center, Hosei University, Koganei, Tokyo, 184-8584, Japan aishiham@hosei.ac.jp.
[Ti] Título:Transcription profile of Escherichia coli: genomic SELEX search for regulatory targets of transcription factors.
[So] Source:Nucleic Acids Res;44(5):2058-74, 2016 Mar 18.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Bacterial genomes are transcribed by DNA-dependent RNA polymerase (RNAP), which achieves gene selectivity through interaction with sigma factors that recognize promoters, and transcription factors (TFs) that control the activity and specificity of RNAP holoenzyme. To understand the molecular mechanisms of transcriptional regulation, the identification of regulatory targets is needed for all these factors. We then performed genomic SELEX screenings of targets under the control of each sigma factor and each TF. Here we describe the assembly of 156 SELEX patterns of a total of 116 TFs performed in the presence and absence of effector ligands. The results reveal several novel concepts: (i) each TF regulates more targets than hitherto recognized; (ii) each promoter is regulated by more TFs than hitherto recognized; and (iii) the binding sites of some TFs are located within operons and even inside open reading frames. The binding sites of a set of global regulators, including cAMP receptor protein, LeuO and Lrp, overlap with those of the silencer H-NS, suggesting that certain global regulators play an anti-silencing role. To facilitate sharing of these accumulated SELEX datasets with the research community, we compiled a database, 'Transcription Profile of Escherichia coli' (www.shigen.nig.ac.jp/ecoli/tec/).
[Mh] Termos MeSH primário: RNA Polimerases Dirigidas por DNA/genética
Escherichia coli/genética
Regulação Bacteriana da Expressão Gênica
Genoma Bacteriano
Fatores de Transcrição/genética
Transcrição Genética
[Mh] Termos MeSH secundário: Sítios de Ligação
Proteína Receptora de AMP Cíclico/genética
Proteína Receptora de AMP Cíclico/metabolismo
DNA Bacteriano/genética
DNA Bacteriano/metabolismo
RNA Polimerases Dirigidas por DNA/metabolismo
Escherichia coli/metabolismo
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Proteína Reguladora de Resposta a Leucina/genética
Proteína Reguladora de Resposta a Leucina/metabolismo
Regiões Promotoras Genéticas
Ligação Proteica
Técnica de Seleção de Aptâmeros
Fatores de Transcrição/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Cyclic AMP Receptor Protein); 0 (DNA, Bacterial); 0 (Escherichia coli Proteins); 0 (LeuO protein, E coli); 0 (Lrp protein, E coli); 0 (Transcription Factors); 138791-20-5 (Leucine-Responsive Regulatory Protein); EC 2.7.7.6 (DNA-Directed RNA Polymerases)
[Em] Mês de entrada:1607
[Cu] Atualização por classe:160322
[Lr] Data última revisão:
160322
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160205
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkw051


  5 / 216 MEDLINE  
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[PMID]:26789099
[Au] Autor:Song N; Cui Y; Li Z; Chen L; Liu S
[Ad] Endereço:1 State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Harbin, China .
[Ti] Título:New Targets and Cofactors for the Transcription Factor LrpA from Mycobacterium tuberculosis.
[So] Source:DNA Cell Biol;35(4):167-76, 2016 Apr.
[Is] ISSN:1557-7430
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Rv3291c (MtbLrpA), a transcriptional regulator, belongs to the leucine-responsive regulatory protein (Lrp) family and is thought to play an important role in Mycobacterium tuberculosis persistence. In this study, we verified 17 novel potential binding sites for MtbLrpA by in vitro binding assays on the basis of previous predictions from an in silico analysis and bacterial one-hybrid (BIH) reporter system. Amino acids, such as tyrosine, phenylalanine, tryptophan, and histidine, strongly affect the binding affinity of MtbLrpA, and vitamins, including B1, B3, B6, VC, B7, B9, B12, VA, and VK3, also decrease MtbLrpA binding affinity. This is the first report regarding that an Lrp-like protein can sense vitamins as an environmental signal. Vitamin supplementation to the environment can change the expression level of the target genes, which provides a potential mechanism for tuberculosis supplementary treatment with vitamins.
[Mh] Termos MeSH primário: Antituberculosos/química
Proteínas de Bactérias/química
Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos
Proteína Reguladora de Resposta a Leucina/química
Mycobacterium tuberculosis
[Mh] Termos MeSH secundário: Proteínas de Bactérias/antagonistas & inibidores
Sítios de Ligação
Proteína Reguladora de Resposta a Leucina/antagonistas & inibidores
Simulação de Acoplamento Molecular
Ligação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Antitubercular Agents); 0 (Bacterial Proteins); 0 (LrpA protein, bacteria); 138791-20-5 (Leucine-Responsive Regulatory Protein)
[Em] Mês de entrada:1608
[Cu] Atualização por classe:160330
[Lr] Data última revisão:
160330
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160121
[St] Status:MEDLINE
[do] DOI:10.1089/dna.2015.3040


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[PMID]:26755158
[Au] Autor:Engstrom MD; Mobley HL
[Ad] Endereço:Department of Microbiology and Immunology, University of Michigan Medical School, University of Michigan, Ann Arbor, Michigan, USA.
[Ti] Título:Regulation of Expression of Uropathogenic Escherichia coli Nonfimbrial Adhesin TosA by PapB Homolog TosR in Conjunction with H-NS and Lrp.
[So] Source:Infect Immun;84(3):811-21, 2016 Jan 11.
[Is] ISSN:1098-5522
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Urinary tract infections (UTIs) are a major burden to human health. The overwhelming majority of UTIs are caused by uropathogenic Escherichia coli (UPEC) strains. Unlike some pathogens, UPEC strains do not have a fixed core set of virulence and fitness factors but do have a variety of adhesins and regulatory pathways. One such UPEC adhesin is the nonfimbrial adhesin TosA, which mediates adherence to the epithelium of the upper urinary tract. The tos operon is AT rich, resides on pathogenicity island aspV, and is not expressed under laboratory conditions. Because of this, we hypothesized that tosA expression is silenced by H-NS. Lrp, based on its prominent function in the regulation of other adhesins, is also hypothesized to contribute to tos operon regulation. Using a variety of in vitro techniques, we mapped both the tos operon promoter and TosR binding sites. We have now identified TosR as a dual regulator of the tos operon, which could control the tos operon in association with H-NS and Lrp. H-NS is a negative regulator of the tos operon, and Lrp positively regulates the tos operon. Exogenous leucine also inhibits Lrp-mediated tos operon positive regulation. In addition, TosR binds to the pap operon, which encodes another important UPEC adhesin, P fimbria. Induction of TosR synthesis reduces production of P fimbria. These studies advance our knowledge of regulation of adhesin expression associated with uropathogen colonization of a host.
[Mh] Termos MeSH primário: Toxinas Bacterianas/metabolismo
Infecções por Escherichia coli/microbiologia
Proteínas de Escherichia coli/metabolismo
Proteínas de Fímbrias/metabolismo
Regulação Bacteriana da Expressão Gênica
Proteína Reguladora de Resposta a Leucina/metabolismo
Proteínas Repressoras/metabolismo
Escherichia coli Uropatogênica/metabolismo
[Mh] Termos MeSH secundário: Adesinas de Escherichia coli/genética
Adesinas de Escherichia coli/metabolismo
Toxinas Bacterianas/genética
Proteínas de Escherichia coli/genética
Proteínas de Fímbrias/genética
Seres Humanos
Proteína Reguladora de Resposta a Leucina/genética
Proteínas de Membrana/genética
Proteínas de Membrana/metabolismo
Óperon
Regiões Promotoras Genéticas
Proteínas Repressoras/genética
Fatores de Transcrição/genética
Fatores de Transcrição/metabolismo
Escherichia coli Uropatogênica/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Adhesins, Escherichia coli); 0 (Bacterial Toxins); 0 (Escherichia coli Proteins); 0 (FimG protein, E coli); 0 (Lrp protein, E coli); 0 (Membrane Proteins); 0 (Repressor Proteins); 0 (TosR protein, E coli); 0 (Transcription Factors); 0 (tosA protein, E coli); 138791-20-5 (Leucine-Responsive Regulatory Protein); 147680-16-8 (Fimbriae Proteins); EC 3.6.3.14 (atpD protein, E coli)
[Em] Mês de entrada:1608
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160113
[St] Status:MEDLINE
[do] DOI:10.1128/IAI.01302-15


  7 / 216 MEDLINE  
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[PMID]:25785689
[Au] Autor:Pollak AJ; Reich NO
[Ad] Endereço:Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States.
[Ti] Título:DNA adenine methyltransferase facilitated diffusion is enhanced by protein-DNA "roadblock" complexes that induce DNA looping.
[So] Source:Biochemistry;54(13):2181-92, 2015 Apr 07.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The genomes of all cells are intimately associated with proteins, which are important for compaction, scaffolding, and gene regulation. Here we show that pre-existing protein-DNA complexes (roadblocks) diminish and-interestingly-enhance the ability of particular sequence-specific proteins to move along DNA to locate their binding sites. We challenge the bacterial DNA adenine methyltransferase (Dam, recognizes 5'-GATC-3') with tightly bound EcoRV ENase-DNA complexes, which bend DNA. A single EcoRV roadblock does not alter processive (multiple modifications) methylation by Dam. This result disfavors a reliance on heavily touted mechanisms involving sliding or short hops for Dam. Specific conformations of two EcoRV roadblocks cause an increase in processivity. The histone-like leucine-responsive regulatory protein (Lrp) binds DNA nonspecifically as an octamer, and also increases Dam's processivity. These results can be explained by our prior demonstration that Dam moves over large regions (>300 bp) within a single DNA molecule using an "intersegmental hopping" mechanism. This mechanism involves the protein hopping between looped DNA segments. Both roadblock systems can cause the DNA to loop and therefore facilitate intersegmental hopping. For Lrp, this only occurs when the Dam sites are separated (by >134bp) such that they can be looped around the protein. Intersegmental hopping may well be a general mechanism for proteins that navigate long distances along compacted DNA. Unlike Dam, EcoRI ENase (recognizes 5'-GAATTC-3') relies extensively on a sliding mechanism, and as expected, Lrp decreases its processivity. Our systematic use of protein roadblocks provides a powerful strategy to differentiate between site location mechanisms.
[Mh] Termos MeSH primário: DNA/metabolismo
Proteínas de Escherichia coli/metabolismo
Difusão Facilitada
DNA Metiltransferases Sítio Específica (Adenina-Específica)/metabolismo
[Mh] Termos MeSH secundário: Sítios de Ligação
DNA/química
Proteínas de Escherichia coli/química
Proteína Reguladora de Resposta a Leucina/química
Proteína Reguladora de Resposta a Leucina/metabolismo
DNA Metiltransferases Sítio Específica (Adenina-Específica)/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Escherichia coli Proteins); 0 (Lrp protein, E coli); 138791-20-5 (Leucine-Responsive Regulatory Protein); 9007-49-2 (DNA); EC 2.1.1.- (DNA modification methylase EcoRV); EC 2.1.1.72 (Site-Specific DNA-Methyltransferase (Adenine-Specific)); EC 2.1.1.72 (dam protein, E coli)
[Em] Mês de entrada:1506
[Cu] Atualização por classe:150407
[Lr] Data última revisão:
150407
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150319
[St] Status:MEDLINE
[do] DOI:10.1021/bi501344r


  8 / 216 MEDLINE  
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[PMID]:25069663
[Au] Autor:Takao M; Yen H; Tobe T
[Ad] Endereço:Department of Biomedical Informatics, Graduate School of Medicine Osaka University, Suita, Osaka, Japan.
[Ti] Título:LeuO enhances butyrate-induced virulence expression through a positive regulatory loop in enterohaemorrhagic Escherichia coli.
[So] Source:Mol Microbiol;93(6):1302-13, 2014 Sep.
[Is] ISSN:1365-2958
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Enterohaemorrhagic Escherichia coli (EHEC) causes bloody diarrhoea and other severe symptoms such as haemorrhagic uraemic syndrome. The expression of virulence genes on the locus for enterocyte effacement (LEE) and associated genes is regulated by a variety of factors, including transcriptional regulators and environmental signals. Butyrate, one of the major short-chain fatty acids present in the intestine, enhances expression of LEE genes and flagella biosynthesis genes in EHEC O157:H7, resulting in increased bacterial adherence and motility. Here, we show that expression of the leuO gene, which encodes a LysR-type transcriptional regulator, is enhanced by butyrate via Lrp, which is also necessary for butyrate-induced responses of LEE genes. LeuO expression induces prolonged activation of the promoter of LEE1 operon, including the ler gene, as well as virulence mechanisms such as microcolony formation. Activation of the LEE1 promoter by LeuO depends on another regulator, called Pch. The response of the leuO promoter to butyrate requires two virulence regulators, Pch and Ler, in addition to Lrp. Pch, Ler and Lrp bind the upstream region of the leuO promoter. Thus, leuO is involved in butyrate-enhanced expression of LEE genes through a positive feedback mechanism, but its expression and action on the LEE1 promoter are dependent on the virulence regulators Pch and Ler.
[Mh] Termos MeSH primário: Butiratos/metabolismo
Escherichia coli Êntero-Hemorrágica/metabolismo
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Fatores de Transcrição/genética
Fatores de Transcrição/metabolismo
Fatores de Virulência/metabolismo
[Mh] Termos MeSH secundário: Sítios de Ligação
Escherichia coli Êntero-Hemorrágica/genética
Escherichia coli Êntero-Hemorrágica/patogenicidade
Regulação Bacteriana da Expressão Gênica
Proteína Reguladora de Resposta a Leucina/metabolismo
Óperon
Fosfoproteínas/genética
Fosfoproteínas/metabolismo
Regiões Promotoras Genéticas
Transativadores/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Butyrates); 0 (Escherichia coli Proteins); 0 (LEE protein, E coli); 0 (Ler protein, E coli); 0 (LeuO protein, E coli); 0 (Lrp protein, E coli); 0 (Phosphoproteins); 0 (Trans-Activators); 0 (Transcription Factors); 0 (Virulence Factors); 138791-20-5 (Leucine-Responsive Regulatory Protein)
[Em] Mês de entrada:1506
[Cu] Atualização por classe:140909
[Lr] Data última revisão:
140909
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140730
[St] Status:MEDLINE
[do] DOI:10.1111/mmi.12737


  9 / 216 MEDLINE  
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[PMID]:24914179
[Au] Autor:Graveline R; Garneau P; Martin C; Mourez M; Hancock MA; Lavoie R; Harel J
[Ad] Endereço:Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Université de Montréal, Saint-Hyacinthe, Quebec, Canada.
[Ti] Título:Leucine-responsive regulatory protein Lrp and PapI homologues influence phase variation of CS31A fimbriae.
[So] Source:J Bacteriol;196(16):2944-53, 2014 Aug 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:CS31A, a K88-related surface antigen specified by the clp operon, is a member of the type P family of adhesive factors and plays a key role in the establishment of disease caused by septicemic and enterotoxigenic Escherichia coli strains. Its expression is under the control of methylation-dependent transcriptional regulation, for which the leucine-responsive regulatory protein (Lrp) is essential. CS31A is preferentially in the OFF state and exhibits distinct regulatory features compared to the regulation of other P family members. In the present study, surface plasmon resonance and DNase I protection assays showed that Lrp binds to the distal moiety of the clp regulatory region with low micromolar affinity compared to its binding to the proximal moiety, which exhibits stronger, nanomolar affinity. The complex formation was also influenced by the addition of PapI or FooI, which increased the affinity of Lrp for the clp distal and proximal regions and was required to induce phase variation. The influence of PapI or FooI, however, was predominantly associated with a more complete shutdown of clp expression, in contrast to what has previously been observed with AfaF (a PapI ortholog). Taken together, these results suggest that the preferential OFF state observed in CS31A cells is mainly due to the weak interaction of the leucine-responsive regulatory protein with the clp distal region and that the PapI homolog favors the OFF phase. Within the large repertoire of fimbrial variants in the P family, our study illustrates that having a fimbrial operon that lacks its own PapI ortholog allows it to be more flexibly regulated by other orthologs in the cell.
[Mh] Termos MeSH primário: Antígenos de Bactérias/biossíntese
Proteínas de Escherichia coli/biossíntese
Proteínas de Escherichia coli/metabolismo
Escherichia coli/genética
Regulação Bacteriana da Expressão Gênica
Proteína Reguladora de Resposta a Leucina/metabolismo
Proteínas Repressoras/metabolismo
[Mh] Termos MeSH secundário: Pegada de DNA
DNA Bacteriano/metabolismo
Regiões Promotoras Genéticas
Ligação Proteica
Ressonância de Plasmônio de Superfície
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Antigens, Bacterial); 0 (DNA, Bacterial); 0 (Escherichia coli Proteins); 0 (Lrp protein, E coli); 0 (PapI protein, E coli); 0 (Repressor Proteins); 138791-20-5 (Leucine-Responsive Regulatory Protein); 144998-09-4 (clpG protein, E coli)
[Em] Mês de entrada:1409
[Cu] Atualização por classe:161019
[Lr] Data última revisão:
161019
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140611
[St] Status:MEDLINE
[do] DOI:10.1128/JB.01622-14


  10 / 216 MEDLINE  
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[PMID]:24039985
[Au] Autor:Chauhan A; Sakamoto C; Ghigo JM; Beloin C
[Ad] Endereço:Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France.
[Ti] Título:Did I pick the right colony? Pitfalls in the study of regulation of the phase variable antigen 43 adhesin.
[So] Source:PLoS One;8(9):e73568, 2013.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Ag43 is an abundant outer membrane autotransporter adhesin present in most commensal and pathogenic Escherichia coli. Expression of the agn43 gene is characterized by a regulated reversible switch or phase variation between the agn43 ON and agn43 OFF states. Although the agn43 regulatory switch leads to a heterogeneous population of ON and OFF bacteria, studies of Ag43 seldom consider potential biases associated with phase variation. We monitored agn43 ON/OFF phase-variation status genetically and phenotypically and we show that the use of populations with random agn43 ON or OFF status could result in misleading conclusions about Ag43 function or regulation. In particular, we demonstrate that Lrp and MqsR, previously identified as agn43 regulators, do not regulate agn43 expression or ON/OFF switch frequency. We also show that biofilm formation in dynamic flow conditions does not influence agn43 ON/OFF switching but physically selects aggregating agn43 ON cells. This indicates that misinterpretation is possible when studying gene expression within biofilms. Finally, we provide evidence that ignoring the initial agn43 ON/OFF status of the E. coli populations studied is likely to bias analyses of phenotypes associated with other E. coli adhesins. This study therefore emphasizes the importance of monitoring Ag43 phase variation and indicates that caution is required when interpreting experiments using strains that are neither deleted for agn43 nor carefully assessed for agn43 ON/OFF status.
[Mh] Termos MeSH primário: Adesinas de Escherichia coli/genética
Biofilmes/crescimento & desenvolvimento
Escherichia coli/fisiologia
Regulação Bacteriana da Expressão Gênica
[Mh] Termos MeSH secundário: Adesinas de Escherichia coli/análise
Adesinas de Escherichia coli/metabolismo
Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Proteína Reguladora de Resposta a Leucina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Adhesins, Escherichia coli); 0 (Escherichia coli Proteins); 0 (Lrp protein, E coli); 0 (MqsR protein, E coli); 0 (antigen 43, E coli); 138791-20-5 (Leucine-Responsive Regulatory Protein)
[Em] Mês de entrada:1406
[Cu] Atualização por classe:150422
[Lr] Data última revisão:
150422
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:130917
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0073568



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