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[PMID]:29281627
[Au] Autor:Schramm FD; Heinrich K; Thüring M; Bernhardt J; Jonas K
[Ad] Endereço:Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
[Ti] Título:An essential regulatory function of the DnaK chaperone dictates the decision between proliferation and maintenance in Caulobacter crescentus.
[So] Source:PLoS Genet;13(12):e1007148, 2017 12.
[Is] ISSN:1553-7404
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Hsp70 chaperones are well known for their important functions in maintaining protein homeostasis during thermal stress conditions. In many bacteria the Hsp70 homolog DnaK is also required for growth in the absence of stress. The molecular reasons underlying Hsp70 essentiality remain in most cases unclear. Here, we demonstrate that DnaK is essential in the α-proteobacterium Caulobacter crescentus due to its regulatory function in gene expression. Using a suppressor screen we identified mutations that allow growth in the absence of DnaK. All mutations reduced the activity of the heat shock sigma factor σ32, demonstrating that the DnaK-dependent inactivation of σ32 is a growth requirement. While most mutations occurred in the rpoH gene encoding σ32, we also identified mutations affecting σ32 activity or stability in trans, providing important new insight into the regulatory mechanisms controlling σ32 activity. Most notably, we describe a mutation in the ATP dependent protease HslUV that induces rapid degradation of σ32, and a mutation leading to increased levels of the house keeping σ70 that outcompete σ32 for binding to the RNA polymerase. We demonstrate that σ32 inhibits growth and that its unrestrained activity leads to an extensive reprogramming of global gene expression, resulting in upregulation of repair and maintenance functions and downregulation of the growth-promoting functions of protein translation, DNA replication and certain metabolic processes. While this re-allocation from proliferative to maintenance functions could provide an advantage during heat stress, it leads to growth defects under favorable conditions. We conclude that Caulobacter has co-opted the DnaK chaperone system as an essential regulator of gene expression under conditions when its folding activity is dispensable.
[Mh] Termos MeSH primário: Caulobacter crescentus/fisiologia
Proteínas de Choque Térmico HSP70/fisiologia
[Mh] Termos MeSH secundário: Proteases Dependentes de ATP/genética
Sequência de Aminoácidos
Proteínas de Bactérias/genética
Caulobacter crescentus/genética
Caulobacter crescentus/metabolismo
RNA Polimerases Dirigidas por DNA/genética
Regulação Bacteriana da Expressão Gênica
Proteínas de Choque Térmico HSP40/genética
Proteínas de Choque Térmico HSP70/genética
Proteínas de Choque Térmico HSP70/metabolismo
Resposta ao Choque Térmico
Chaperonas Moleculares/genética
Fator sigma/genética
Fatores de Transcrição/genética
Transcrição Genética/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (HSP40 Heat-Shock Proteins); 0 (HSP70 Heat-Shock Proteins); 0 (Molecular Chaperones); 0 (Sigma Factor); 0 (Transcription Factors); EC 2.7.7.6 (DNA-Directed RNA Polymerases); EC 3.4.21.- (ATP-Dependent Proteases)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180227
[Lr] Data última revisão:
180227
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171228
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pgen.1007148


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[PMID]:28471404
[Au] Autor:Aubee JI; Olu M; Thompson KM
[Ad] Endereço:Department of Microbiology, College of Medicine, Howard University, Washington, DC 20059, USA. joseph.aubee@howard.edu.
[Ti] Título:TrmL and TusA Are Necessary for rpoS and MiaA Is Required for hfq Expression in Escherichia coli.
[So] Source:Biomolecules;7(2), 2017 May 04.
[Is] ISSN:2218-273X
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Previous work demonstrated that efficient RNA Polymerase sigma S-subunit (RpoS) translation requires the N6-isopentenyladenosine i6A37 transfer RNA (tRNA) modification for UUX-Leu decoding. Here we investigate the effect of two additional tRNA modification systems on RpoS translation; the analysis was also extended to another High UUX-leucine codon (HULC) protein, Host Factor for phage Qß (Hfq). One tRNA modification, the addition of the 2'-O-methylcytidine/uridine 34 (C/U34m) tRNA modification by tRNA (cytidine/uridine-2'O)-ribose methyltransferase L (TrmL), requires the presence of the 6-isopentenyladenosine 37 (i6A37) and therefore it seemed possible that the defect in RpoS translation in the absence of i6A37 prenyl transferase (MiaA) was in fact due to the inability to add the C/U34m modification to UUX-Leu tRNAs. The second modification, addition of 2-thiouridine (s²U), part of (mnm5s²U34), is dependent on tRNA 2-thiouridine synthesizing protein A (TusA), previously shown to affect RpoS levels. We compared expression of P - translational fusions carrying wild-type UUX leucine codons with derivatives in which UUX codons were changed to CUX codons, in the presence and absence of TrmL or TusA. The absence of these proteins, and therefore presumably the modifications they catalyze, both abolished P - - translation activity. UUX-Leu to CUX-Leu codon mutations in suppressed the requirement for P - - expression. Thus, it is likely that the C/U34m and s²U34 tRNA modifications are necessary for full translation. We also measured P - translational fusion activity in the absence of C/U34m ( ) or i6A37 ( ). The absence of i6A37 resulted in decreased P - expression, consistent with a role for i6A37 tRNA modification for translation.
[Mh] Termos MeSH primário: Alquil e Aril Transferases/metabolismo
Proteínas de Bactérias/metabolismo
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Escherichia coli/metabolismo
Regulação Bacteriana da Expressão Gênica
Fator Proteico 1 do Hospedeiro/genética
Metiltransferases/metabolismo
Fator sigma/metabolismo
[Mh] Termos MeSH secundário: Sequência de Bases
Escherichia coli/genética
RNA de Transferência/genética
RNA de Transferência/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Escherichia coli Proteins); 0 (Hfq protein, E coli); 0 (Host Factor 1 Protein); 0 (Sigma Factor); 0 (TusA protein, E coli); 0 (sigma factor KatF protein, Bacteria); 9014-25-9 (RNA, Transfer); EC 2.1.1.- (Methyltransferases); EC 2.1.1.- (TrmL protein, E coli); EC 2.5.- (Alkyl and Aryl Transferases); EC 2.5.1.27 (adenylate isopentenyltransferase)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180219
[Lr] Data última revisão:
180219
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE


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[PMID]:28468910
[Au] Autor:Dapa T; Fleurier S; Bredeche MF; Matic I
[Ad] Endereço:INSERM U1001, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine Paris Descartes, 75014, France.
[Ti] Título:The SOS and RpoS Regulons Contribute to Bacterial Cell Robustness to Genotoxic Stress by Synergistically Regulating DNA Polymerase Pol II.
[So] Source:Genetics;206(3):1349-1360, 2017 07.
[Is] ISSN:1943-2631
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Mitomycin C (MMC) is a genotoxic agent that induces DNA cross-links, DNA alkylation, and the production of reactive oxygen species (ROS). MMC induces the SOS response and RpoS regulons in SOS-encoded functions are required for DNA repair, whereas the RpoS regulon is typically induced by metabolic stresses that slow growth. Thus, induction of the RpoS regulon by MMC may be coincidental, because DNA damage slows growth; alternatively, the RpoS regulon may be an adaptive response contributing to cell survival. In this study, we show that the RpoS regulon is primarily induced by MMC-induced ROS production. We also show that RpoS regulon induction is required for the survival of MMC-treated growing cells. The major contributor to RpoS-dependent resistance to MMC treatment is DNA polymerase Pol II, which is encoded by the gene belonging to the SOS regulon. The observation that gene expression is controlled by the two major stress response regulons that are required to maximize survival and fitness further emphasizes the key role of this DNA polymerase as an important factor in genome stability.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Dano ao DNA
Proteínas de Escherichia coli/metabolismo
Resposta SOS (Genética)
Fator sigma/metabolismo
[Mh] Termos MeSH secundário: Antibacterianos/toxicidade
Proteínas de Bactérias/genética
Escherichia coli/efeitos dos fármacos
Escherichia coli/genética
Escherichia coli/metabolismo
Proteínas de Escherichia coli/genética
Mitomicina/toxicidade
Mutagênicos/toxicidade
Espécies Reativas de Oxigênio/metabolismo
Regulon
Fator sigma/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Bacterial Proteins); 0 (Escherichia coli Proteins); 0 (Mutagens); 0 (Reactive Oxygen Species); 0 (Sigma Factor); 0 (polB protein, E coli); 0 (sigma factor KatF protein, Bacteria); 50SG953SK6 (Mitomycin)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171213
[Lr] Data última revisão:
171213
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1534/genetics.116.199471


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[PMID]:28470798
[Au] Autor:Parker A; Cureoglu S; De Lay N; Majdalani N; Gottesman S
[Ad] Endereço:Laboratory of Molecular Biology, National Cancer Institute, Bethesda, MD, 20892, USA.
[Ti] Título:Alternative pathways for Escherichia coli biofilm formation revealed by sRNA overproduction.
[So] Source:Mol Microbiol;105(2):309-325, 2017 Jul.
[Is] ISSN:1365-2958
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Small regulatory RNAs have major roles in many regulatory circuits in Escherichia coli and other bacteria, including the transition from planktonic to biofilm growth. We tested Hfq-dependent sRNAs in E. coli for their ability, when overproduced, to inhibit or stimulate biofilm formation, in two different growth media. We identify two mutually exclusive pathways for biofilm formation. In LB, PgaA, encoding an adhesion export protein, played a critical role; biofilm was independent of the general stress factor RpoS or CsgD, regulator of curli and other biofilm genes. The PgaA-dependent pathway was stimulated upon overproduction of DsrA, via negative regulation of H-NS, or of GadY, likely by titration of CsrA. In yeast extract casamino acids (YESCA) media, biofilm was dependent on RpoS and CsgD, but independent of PgaA; RpoS appears to indirectly negatively regulate the PgaA-dependent pathway in YESCA medium. Deletions of most sRNAs had very little effect on biofilm, although deletion of hfq, encoding an RNA chaperone, was defective in both LB and YESCA. Deletion of ArcZ, a small RNA activator of RpoS, decreased biofilm in YESCA; only a portion of this defect could be bypassed by overproduction of RpoS. Overall, sRNAs highlight different pathways to biofilm formation.
[Mh] Termos MeSH primário: Proteínas da Membrana Bacteriana Externa/metabolismo
Biofilmes/crescimento & desenvolvimento
Proteínas de Escherichia coli/metabolismo
Pequeno RNA não Traduzido/metabolismo
[Mh] Termos MeSH secundário: Proteínas da Membrana Bacteriana Externa/genética
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Sítios de Ligação
Escherichia coli/genética
Proteínas de Escherichia coli/genética
Regulação Bacteriana da Expressão Gênica/genética
Fator Proteico 1 do Hospedeiro/metabolismo
RNA Bacteriano/metabolismo
RNA Mensageiro/metabolismo
Pequeno RNA não Traduzido/genética
Fator sigma/genética
Fator sigma/metabolismo
Transativadores/genética
Transativadores/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Outer Membrane Proteins); 0 (Bacterial Proteins); 0 (CsgD protein, E coli); 0 (Escherichia coli Proteins); 0 (Host Factor 1 Protein); 0 (RNA, Bacterial); 0 (RNA, Messenger); 0 (RNA, Small Untranslated); 0 (Sigma Factor); 0 (Trans-Activators); 0 (pgaA protein, E coli); 0 (sigma factor KatF protein, Bacteria)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171128
[Lr] Data última revisão:
171128
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1111/mmi.13702


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[PMID]:28988932
[Au] Autor:Chen J; Wassarman KM; Feng S; Leon K; Feklistov A; Winkelman JT; Li Z; Walz T; Campbell EA; Darst SA
[Ad] Endereço:Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA.
[Ti] Título:6S RNA Mimics B-Form DNA to Regulate Escherichia coli RNA Polymerase.
[So] Source:Mol Cell;68(2):388-397.e6, 2017 Oct 19.
[Is] ISSN:1097-4164
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Noncoding RNAs (ncRNAs) regulate gene expression in all organisms. Bacterial 6S RNAs globally regulate transcription by binding RNA polymerase (RNAP) holoenzyme and competing with promoter DNA. Escherichia coli (Eco) 6S RNA interacts specifically with the housekeeping σ -holoenzyme (Eσ ) and plays a key role in the transcriptional reprogramming upon shifts between exponential and stationary phase. Inhibition is relieved upon 6S RNA-templated RNA synthesis. We report here the 3.8 Å resolution structure of a complex between 6S RNA and Eσ determined by single-particle cryo-electron microscopy and validation of the structure using footprinting and crosslinking approaches. Duplex RNA segments have A-form C3' endo sugar puckers but widened major groove widths, giving the RNA an overall architecture that mimics B-form promoter DNA. Our results help explain the specificity of Eco 6S RNA for Eσ and show how an ncRNA can mimic B-form DNA to directly regulate transcription by the DNA-dependent RNAP.
[Mh] Termos MeSH primário: DNA de Forma B/metabolismo
DNA Bacteriano/metabolismo
RNA Polimerases Dirigidas por DNA/metabolismo
Proteínas de Escherichia coli/metabolismo
Escherichia coli/metabolismo
RNA Bacteriano/metabolismo
RNA não Traduzido/metabolismo
Fator sigma/metabolismo
[Mh] Termos MeSH secundário: DNA de Forma B/genética
DNA Bacteriano/genética
RNA Polimerases Dirigidas por DNA/genética
Escherichia coli/genética
Proteínas de Escherichia coli/genética
RNA Bacteriano/genética
RNA não Traduzido/genética
Fator sigma/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (6S RNA); 0 (DNA, B-Form); 0 (DNA, Bacterial); 0 (Escherichia coli Proteins); 0 (RNA, Bacterial); 0 (RNA, Untranslated); 0 (Sigma Factor); EC 2.7.7.- (RNA polymerase sigma 70); EC 2.7.7.6 (DNA-Directed RNA Polymerases)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171115
[Lr] Data última revisão:
171115
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171010
[St] Status:MEDLINE


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[PMID]:28945818
[Au] Autor:Ainelo H; Lahesaare A; Teppo A; Kivisaar M; Teras R
[Ad] Endereço:Chair of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia.
[Ti] Título:The promoter region of lapA and its transcriptional regulation by Fis in Pseudomonas putida.
[So] Source:PLoS One;12(9):e0185482, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:LapA is the biggest protein in Pseudomonas putida and a key factor for biofilm formation. Its importance and posttranslational regulation is rather thoroughly studied but less is known about the transcriptional regulation. Here we give evidence that transcription of lapA in LB-grown bacteria is initiated from six promoters, three of which display moderate RpoS-dependence. The global transcription regulator Fis binds to the lapA promoter area at six positions in vitro, and Fis activates the transcription of lapA while overexpressed in cells. Two of the six Fis binding sites, Fis-A7 and Fis-A5, are necessary for the positive effect of Fis on the transcription of lapA in vivo. Our results indicate that Fis binding to the Fis-A7 site increases the level of transcription from the most distal promoter of lapA, whereas Fis binding to the Fis-A5 site could be important for modifying the promoter area topology.
[Mh] Termos MeSH primário: Genes Bacterianos
Pseudomonas putida/genética
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Sequência de Bases
Sítios de Ligação/genética
Biofilmes/crescimento & desenvolvimento
Mapeamento Cromossômico
DNA Bacteriano/genética
Fator Proteico para Inversão de Estimulação/genética
Fator Proteico para Inversão de Estimulação/metabolismo
Regulação Bacteriana da Expressão Gênica
Regiões Promotoras Genéticas
Pseudomonas putida/fisiologia
Fator sigma/genética
Fator sigma/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (DNA, Bacterial); 0 (Factor For Inversion Stimulation Protein); 0 (Sigma Factor); 0 (sigma factor KatF protein, Bacteria)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171016
[Lr] Data última revisão:
171016
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170926
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0185482


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[PMID]:28934483
[Au] Autor:Goutam K; Gupta AK; Gopal B
[Ad] Endereço:Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India.
[Ti] Título:The fused SnoaL_2 domain in the Mycobacterium tuberculosis sigma factor σJ modulates promoter recognition.
[So] Source:Nucleic Acids Res;45(16):9760-9772, 2017 Sep 19.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Extra-cytoplasmic function (ECF) σ-factors are widespread in bacteria, linking environmental stimuli with changes in gene expression. These transcription factors span several phylogenetically distinct groups and are remarkably diverse in their activation and regulatory mechanisms. Here, we describe the structural and biochemical features of a Mycobacterium tuberculosis ECF factor σJ that suggests that the SnoaL_2 domain at the C-terminus can modulate the activity of this initiation factor in the absence of a cognate regulatory anti-σ factor. M. tuberculosis σJ can bind promoter DNA in vitro; this interaction is substantially impaired by the removal of the SnoaL_2 domain. This finding is consistent with assays to evaluate σJ-mediated gene expression. Structural similarity of the SnoaL_2 domain with epoxide hydrolases also suggests a novel functional role for this domain. The conserved sequence features between M. tuberculosis σJ and other members of the ECF41 family of σ-factors suggest that the regulatory mechanism involving the C-terminal SnoaL_2 domain is likely to be retained in this family of proteins. These studies suggest that the ECF41 family of σ-factors incorporate features of both-the σ70 family and bacterial one-component systems thereby providing a direct mechanism to implement environment-mediated transcription changes.
[Mh] Termos MeSH primário: Mycobacterium tuberculosis/genética
Regiões Promotoras Genéticas
Fator sigma/química
Fator sigma/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Cristalografia por Raios X
Simulação de Dinâmica Molecular
Conformação Proteica
Domínios Proteicos
Fator sigma/genética
Ressonância de Plasmônio de Superfície
beta-Galactosidase/genética
beta-Galactosidase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Sigma Factor); EC 3.2.1.23 (beta-Galactosidase)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170922
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx609


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[PMID]:28934467
[Au] Autor:Wu P; Liu X; Yang L; Sun Y; Gong Q; Wu J; Shi Y
[Ad] Endereço:Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China.
[Ti] Título:The important conformational plasticity of DsrA sRNA for adapting multiple target regulation.
[So] Source:Nucleic Acids Res;45(16):9625-9639, 2017 Sep 19.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:In bacteria, small non-coding RNAs (sRNAs) could function in gene regulations under variable stress responses. DsrA is an ∼90-nucleotide Hfq-dependent sRNA found in Escherichia coli. It regulates the translation and degradation of multiple mRNAs, such as rpoS, hns, mreB and rbsD mRNAs. However, its functional structure and particularly how it regulates multiple mRNAs remain obscure. Using NMR, we investigated the solution structures of the full-length and isolated stem-loops of DsrA. We first solved the NMR structure of the first stem-loop (SL1), and further studied the melting process of the SL1 induced by the base-pairing with the rpoS mRNA and the A-form duplex formation of the DsrA/rpoS complex. The secondary structure of the second stem-loop (SL2) was also determined, which contains a lower stem and an upper stem with distinctive stability. Interestingly, two conformational states of SL2 in dynamic equilibrium were observed in our NMR spectra, suggesting that the conformational selection may occur during the base-pairing between DsrA and mRNAs. In summary, our study suggests that the conformational plasticity of DsrA may represent a special mechanism sRNA employed to deal with its multiple regulatory targets of mRNA.
[Mh] Termos MeSH primário: Pequeno RNA não Traduzido/química
Pequeno RNA não Traduzido/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Pareamento de Bases
Escherichia coli/genética
Espectroscopia de Ressonância Magnética
Conformação de Ácido Nucleico
RNA Mensageiro/química
RNA Mensageiro/metabolismo
Fator sigma/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (DsrA RNA, E coli); 0 (RNA, Messenger); 0 (RNA, Small Untranslated); 0 (Sigma Factor); 0 (sigma factor KatF protein, Bacteria)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170922
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx570


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[PMID]:28931045
[Au] Autor:Fujise K; Kikuchi Y; Kokubu E; Okamoto-Shibayama K; Ishihara K
[Ad] Endereço:Department of Microbiology, Tokyo Dental College, Chiyoda-ku, Tokyo, Japan.
[Ti] Título:Effect of extracytoplasmic function sigma factors on autoaggregation, hemagglutination, and cell surface properties of Porphyromonas gingivalis.
[So] Source:PLoS One;12(9):e0185027, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Porphyromonas gingivalis is a bacterium frequently isolated from chronic periodontal lesions and is involved in the development of chronic periodontitis. To colonize the gingival crevice, P. gingivalis has to adapt to environmental stresses. Microbial gene expression is regulated by transcription factors such as those in two-component systems and extracytoplasmic function (ECF) sigma factors. ECF sigma factors are involved in the regulation of environmental stress response genes; however, the roles of individual ECF sigma factors are largely unknown. The purpose of this study was to investigate the functions, including autoaggregation, hemagglutination, gingipain activity, susceptibility to antimicrobial agents, and surface structure formation, of P. gingivalis ECF sigma factors encoded by SigP (PGN_0274), SigCH (PGN_0319), PGN_0450, PGN_0970, and SigH (PGN_1740). Various physiological aspects of the sigP mutant were affected; autoaggregation was significantly decreased at 60 min (p < 0.001), hemagglutination activity was markedly reduced, and enzymatic activities of Kgp and Rgps were significantly decreased (p < 0.001). The other mutants also showed approximately 50% reduction in Rgps activity. Kgp activity was significantly reduced in the sigH mutant (p < 0.001). No significant differences in susceptibilities to tetracycline and ofloxacin were observed in the mutants compared to those of the wild-type strain. However, the sigP mutant displayed an increased susceptibility to ampicillin, whereas the PGN_0450 and sigH mutants showed reduced susceptibility. Transmission electron microscopy images revealed increased levels of outer membrane vesicles formed at the cell surfaces of the sigP mutant. These results indicate that SigP is important for bacterial surface-associated activities, including gingipain activity, autoaggregation, hemagglutination, vesicle formation, and antimicrobial susceptibility.
[Mh] Termos MeSH primário: Infecções por Bacteroidaceae/microbiologia
Periodontite Crônica/microbiologia
Hemaglutinação
Porphyromonas gingivalis/fisiologia
Fator sigma/metabolismo
[Mh] Termos MeSH secundário: Animais
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Periodontite Crônica/genética
Feminino
Regulação Bacteriana da Expressão Gênica
Camundongos
Camundongos Endogâmicos BALB C
Mutação/genética
Fator sigma/genética
Propriedades de Superfície
Virulência
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Sigma Factor)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171017
[Lr] Data última revisão:
171017
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170921
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0185027


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[PMID]:28781126
[Au] Autor:Coulson GB; Johnson BK; Zheng H; Colvin CJ; Fillinger RJ; Haiderer ER; Hammer ND; Abramovitch RB
[Ad] Endereço:Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
[Ti] Título:Targeting Mycobacterium tuberculosis Sensitivity to Thiol Stress at Acidic pH Kills the Bacterium and Potentiates Antibiotics.
[So] Source:Cell Chem Biol;24(8):993-1004.e4, 2017 Aug 17.
[Is] ISSN:2451-9456
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Mycobacterium tuberculosis (Mtb) must sense and adapt to immune pressures such as acidic pH during pathogenesis. The goal of this study was to isolate compounds that inhibit acidic pH resistance, thus defining virulence pathways that are vulnerable to chemotherapy. Here, we report that the compound AC2P36 selectively kills Mtb at acidic pH and potentiates the bactericidal activity of isoniazid, clofazimine, and diamide. We show that AC2P36 activity is associated with thiol stress and causes an enhanced accumulation of intracellular reactive oxygen species at acidic pH. Mechanism of action studies demonstrate that AC2P36 directly depletes Mtb thiol pools, with enhanced depletion of free thiols at acidic pH. These findings support that Mtb is especially vulnerable to thiol stress at acidic pH and that chemical depletion of thiol pools is a promising target to promote Mtb killing and potentiation of antimicrobials.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Mycobacterium tuberculosis/efeitos dos fármacos
Pirimidinas/farmacologia
Compostos de Sulfidrila/metabolismo
Sulfonas/farmacologia
[Mh] Termos MeSH secundário: Antibacterianos/química
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Glutationa/química
Concentração de Íons de Hidrogênio
Mycobacterium tuberculosis/crescimento & desenvolvimento
Estresse Oxidativo/efeitos dos fármacos
Pirimidinas/química
Espécies Reativas de Oxigênio/metabolismo
Fator sigma/genética
Fator sigma/metabolismo
Relação Estrutura-Atividade
Compostos de Sulfidrila/química
Sulfonas/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (5-chloro-N-(3-chloro-4-methoxyphenyl)-2-methylsulfonylpyrimidine-4-carboxamide); 0 (Anti-Bacterial Agents); 0 (Bacterial Proteins); 0 (Pyrimidines); 0 (Reactive Oxygen Species); 0 (SigH protein, bacteria); 0 (Sigma Factor); 0 (Sulfhydryl Compounds); 0 (Sulfones); GAN16C9B8O (Glutathione)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171009
[Lr] Data última revisão:
171009
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170808
[St] Status:MEDLINE



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