scholarly journals Contribution of the PhoP-PhoQ and PmrA-PmrB Two-Component Regulatory Systems to Mg2+-Induced Gene Regulation in Pseudomonas aeruginosa

2006 ◽  
Vol 188 (11) ◽  
pp. 3995-4006 ◽  
Author(s):  
Joseph B. McPhee ◽  
Manjeet Bains ◽  
Geoff Winsor ◽  
Shawn Lewenza ◽  
Agnieszka Kwasnicka ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Transcriptional Profiling ◽  
Polymyxin B ◽  
Dependent Manner ◽  
Binding Assays ◽  
Response Regulators ◽  
Binding Motifs ◽  
Regulatory Systems ◽  
Two Component ◽  
Genes Encoding

ABSTRACT When grown in divalent cation-limited medium, Pseudomonas aeruginosa becomes resistant to cationic antimicrobial peptides and polymyxin B. This resistance is regulated by the PhoP-PhoQ and PmrA-PmrB two-component regulatory systems. To further characterize Mg2+ regulation in P. aeruginosa, microarray transcriptional profiling was conducted to compare wild-type P. aeruginosa grown under Mg2+-limited and Mg2+-replete conditions to isogenic phoP and pmrA mutants grown under Mg2+-limited conditions. Under Mg2+-limited conditions (0.02 mM Mg2+), approximately 3% of the P. aeruginosa genes were differentially expressed compared to the expression in bacteria grown under Mg2+-replete conditions (2 mM Mg2+). Only a modest subset of the Mg2+-regulated genes were regulated through either PhoP or PmrA. To determine which genes were directly regulated, a bioinformatic search for conserved binding motifs was combined with confirmatory reverse transcriptase PCR and gel shift promoter binding assays, and the results indicated that very few genes were directly regulated by these response regulators. It was found that in addition to the previously known oprH-phoP-phoQ operon and the pmrHFIJKLM-ugd operon, the PA0921 and PA1343 genes, encoding small basic proteins, were regulated by Mg2+ in a PhoP-dependent manner. The number of known PmrA-regulated genes was expanded to include the PA1559-PA1560, PA4782-PA4781, and feoAB operons, in addition to the previously known PA4773-PA4775-pmrAB and pmrHFIJKLM-ugd operons.

scholarly journals The ChrA-ChrS and HrrA-HrrS Signal Transduction Systems Are Required for Activation of the hmuO Promoter and Repression of the hemA Promoter in Corynebacterium diphtheriae

2007 ◽  
Vol 75 (5) ◽  
pp. 2421-2431 ◽  
Author(s):  
Lori A. Bibb ◽  
Carey A. Kunkle ◽  
Michael P. Schmitt
Keyword(s):  
Corynebacterium Diphtheriae ◽  
Heme Iron ◽  
Dependent Manner ◽  
Two Component System ◽  
Component System ◽  
Regulatory Systems ◽  
Component Systems ◽  
Two Component ◽  
Genes Encoding ◽  
Two Component Systems

ABSTRACT Transcription of the Corynebacterium diphtheriae hmuO gene, which encodes a heme oxygenase involved in heme iron utilization, is activated in a heme- or hemoglobin-dependent manner in part by the two-component system ChrA-ChrS. Mutation of either the chrA or the chrS gene resulted in a marked reduction of hemoglobin-dependent activation at the hmuO promoter in C. diphtheriae; however, it was observed that significant levels of hemoglobin-dependent expression were maintained in the mutants, suggesting that an additional activator is involved in regulation. A BLAST search of the C. diphtheriae genome sequence revealed a second two-component system, encoded by DIP2268 and DIP2267, that shares similarity with ChrS and ChrA, respectively; we have designated these genes hrrS (DIP2268) and hrrA (DIP2267). Analysis of hmuO promoter expression demonstrated that hemoglobin-dependent activity was fully abolished in strains from which both the chrA-chrS and the hrrA-hrrS two-component systems were deleted. Similarly, deletion of the sensor kinase genes chrS and hrrS or the genes encoding both of the response regulators chrA and hrrA also eliminated hemoglobin-dependent activation at the hmuO promoter. We also show that the regulators ChrA-ChrS and HrrA-HrrS are involved in the hemoglobin-dependent repression of the promoter upstream of hemA, which encodes a heme biosynthesis enzyme. Evidence for cross talk between the ChrA-ChrS and HrrA-HrrS systems is presented. In conclusion, these findings demonstrate that the ChrA-ChrS and HrrA-HrrS regulatory systems are critical for full hemoglobin-dependent activation at the hmuO promoter and also suggest that these two-component systems are involved in the complex mechanism of the regulation of heme homeostasis in C. diphtheriae.

scholarly journals Alterations in Two-Component Regulatory Systems of phoPQ and pmrAB Are Associated with Polymyxin B Resistance in Clinical Isolates of Pseudomonas aeruginosa

2009 ◽  
Vol 53 (12) ◽  
pp. 5150-5154 ◽  
Author(s):  
Kaddy Barrow ◽  
Dong H. Kwon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Polymyxin B ◽  
Clinical Isolates ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Strain Pao1 ◽  
Truncated Protein ◽  
Regulatory Systems ◽  
Two Component

ABSTRACT Polymyxins are often the only option to treat acquired multidrug-resistant Pseudomonas aeruginosa. Polymyxin susceptibility in P. aeruginosa PAO1 is associated with the lipopolysaccharide structure that is determined by arnBCADTEF and modulated by phoPQ and pmrAB. We examined five clonally unrelated clinical isolates of polymyxin B-resistant P. aeruginosa to investigate the molecular basis of polymyxin resistance. All isolates grew with 4 μg/ml polymyxin B (MIC, 8 μg/ml), whereas P. aeruginosa PAO1 grew with 0.25 μg/ml polymyxin B (MIC, 0.5 μg/ml). The resistant isolates were converted to susceptible ones (the MICs fell from 8 to 0.5 μg/ml) following the introduction of phoPQ (four isolates) and pmrAB (one isolate), which had been cloned from strain PAO1. DNA sequence analysis revealed that a single-nucleotide substitution in three isolates replaced a single amino acid of PhoQ, the deletion of 17 nucleotides in one isolate truncated the protein of PhoQ, and two nucleotide substitutions in one isolate replaced two amino acids of PmrB. The involvement of these amino acid substitutions or the truncated protein of PhoQ and PmrB in polymyxin B resistance was confirmed using strain PAO1 lacking phoPQ or pmrAB that was transformed by phoPQ or pmrAB containing the amino acid substitutions or the truncated protein. The resistant clinical isolates were sensitized by the inactivation of arnBCADTEF (the MICs fell from 8 to 0.5 μg/ml). These results suggest that polymyxin B resistance among clinical isolates of P. aeruginosa is associated with alterations in two-component regulatory systems of phoPQ or pmrAB.

scholarly journals The Pseudomonas aeruginosa PhoP-PhoQ Two-Component Regulatory System Is Induced upon Interaction with Epithelial Cells and Controls Cytotoxicity and Inflammation

2012 ◽  
Vol 80 (9) ◽  
pp. 3122-3131 ◽  
Author(s):  
Shaan L. Gellatly ◽  
Brittany Needham ◽  
Laurence Madera ◽  
M. Stephen Trent ◽  
Robert E. W. Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Lipid A ◽  
Regulatory System ◽  
Dependent Manner ◽  
Wild Type ◽  
Content Type ◽  
Regulatory Systems ◽  
Two Component ◽  
Inflammatory Phenotype

ABSTRACTThe adaptation ofPseudomonas aeruginosato its environment, including the host, is tightly controlled by its network of regulatory systems. The two-component regulatory system PhoPQ has been shown to play a role in the virulence and polymyxin resistance ofP. aeruginosaas well as several other Gram-negative species. Dysregulation of this system has been demonstrated in clinical isolates, yet how it affects virulence ofP. aeruginosais unknown. To investigate this, an assay was used whereby bacteria were cocultured with human bronchial epithelial cells. The interaction of wild-type (WT) bacteria that had adhered to epithelial cells led to a large upregulation of the expression of theoprH-phoP-phoQoperon and its target, thearnlipopolysaccharide (LPS) modification operon, in a PhoQ-dependent manner, compared to cells in the supernatant that had failed to adhere. Relative to the wild type, aphoQmutant cocultured on epithelial cells produced less secreted protease and lipase and, like thephoQmutant,piv,lipH, andlasBmutants demonstrated reduced cytotoxicity toward epithelial cells. Mutation inphoQalso resulted in alterations to lipid A and to increased inflammatory LPS. These data indicate that mutation ofphoQresults in a phenotype that is similar to the less virulent but more inflammatory phenotype of clinical strains isolated from chronic-stage cystic fibrosis lung infections.

scholarly journals The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (8) ◽  
pp. 3982
Author(s):  
Karolina Kotecka ◽  
Adam Kawalek ◽  
Kamil Kobylecki ◽  
Aneta Agnieszka Bartosik
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Transcriptional Profiling ◽  
Mrna Level ◽  
Transcriptional Regulators ◽  
Resistance Mechanisms ◽  
Chronic Infections ◽  
Environmental Signals ◽  
Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

scholarly journals Predicted Functional and Structural Diversity of Receiver Domains in Fungal Two-Component Regulatory Systems

mSphere ◽  
2021 ◽  
Author(s):  
Robert B. Bourret ◽  
Clay A. Foster ◽  
William E. Goldman
Keyword(s):  
Structural Diversity ◽  
Response Regulators ◽  
Histidine Kinases ◽  
Receiver Domain ◽  
Regulatory Systems ◽  
Two Component

Fungal two-component regulatory systems incorporate receiver domains into hybrid histidine kinases (HHKs) and response regulators. We constructed a nonredundant database of 670 fungal receiver domain sequences from 51 species sampled from nine fungal phyla.

scholarly journals Pseudomonas syringae Two-Component Response Regulator RhpR Regulates Promoters Carrying an Inverted Repeat Element

2010 ◽  
Vol 23 (7) ◽  
pp. 927-939 ◽  
Author(s):  
Xin Deng ◽  
Lefu Lan ◽  
Yanmei Xiao ◽  
Megan Kennelly ◽  
Jian-Min Zhou ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Inverted Repeat ◽  
Response Regulator ◽  
Effector Proteins ◽  
Dependent Manner ◽  
Type Iii ◽  
Regulatory Cascade ◽  
Two Component ◽  
Genes Encoding ◽  
Element Activity

The two-component system RhpRS was identified in Pseudomonas syringae as a regulator of the genes encoding the type III secretion system and type III effector proteins (together called the T3 genes). In the absence of the sensor kinase RhpS, the response regulator RhpR represses the induction of the T3 gene regulatory cascade consisting of hrpRS, hrpL, and the T3 genes in a phosphorylation-dependent manner. The repressor activity of RhpR is inhibited by RhpS, which presumably acts as a phosphatase under the T3 gene inducing conditions. Here, we show that RhpR binds and induces its own promoter in a phosphorylation-dependent manner. Deletion and mutagenesis analyses revealed an inverted repeat (IR) element, GTATC-N6-GATAC, in the rhpR promoter that confers the RhpR-dependent induction. Computational search of the P. syringae genomes for the putative IR elements and Northern blot analysis of the genes with a putative IR element in the promoter region uncovered five genes that were upregulated and two genes that were downregulated in an RhpR-dependent manner. Two genes that were strongly induced by RhpR were assayed for the IR element activity in gene regulation and, in both cases, the IR element mediated the RhpR-dependent gene induction. Chromatin immunoprecipitation assays indicated that RhpR binds the promoters containing a putative IR element but not the hrpR and hrpL promoters that do not have an IR element, suggesting that RhpR indirectly regulates the transcriptional cascade of hrpRS, hrpL, and the T3 genes.

The SagS sensory protein modulates biofilm formation and c-di-GMP levels by Pseudomonas aeruginosa in response to glucose-6-phosphate.

2020 ◽  
Author(s):  
Soyoung Park ◽  
Jozef Dingemans ◽  
Madison Gowett ◽  
Karin Sauer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Genetic Analysis ◽  
Signaling Pathway ◽  
Biofilm Formation ◽  
Phosphate Concentration ◽  
Dependent Manner ◽  
Diguanylate Cyclase ◽  
Swarming Motility ◽  
Two Component ◽  
Insight Into

<p>In <em>Pseudomonas aeruginosa</em>, the orphan two-component sensor SagS contributes to both, the transition to biofilm formation and to biofilm cells gaining their heightened tolerance to antimicrobials. However, little is known about the identity of the signals or conditions sensed by SagS to induce the switch to the sessile, drug tolerant mode of growth. Using a modified Biolog phenotype assay to screen for compounds that modulate attachment in a SagS-dependent manner, we identified glucose-6-phosphate to enhance attachment in a manner dependent on the glucose-6-phosphate concentration and SagS. The stimulatory effect was not limited to the attachment as glucose-6-phosphate likewise enhanced biofilm formation. We show that exposure to glucose-6-phosphate results in decreased swarming motility but increased cellular c-di-GMP levels in biofilms. Genetic analysis indicated that the diguanylate cyclase NicD is an activator of biofilm formation and is not only required for enhanced biofilm formation in response to glucose-6-phosphate but also interacts with SagS. Our findings indicate glucose-6-phosphate to likely mimic a signal or conditions sensed by SagS to activate its motile-sessile switch function. Additionally, our findings provide new insight into the interfaces between the ligand-mediated TCS signaling pathway and c-di-GMP levels.</p>

scholarly journals Novel roles for two-component regulatory systems in cytotoxicity and virulence-related properties in Pseudomonas aeruginosa

2018 ◽  
Vol 4 (1) ◽  
pp. 173-191 ◽  
Author(s):  
Shaan L. Gellatly ◽  
◽  
Manjeet Bains ◽  
Elena B.M. Breidenstein ◽  
Janine Strehmel ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Regulatory Systems ◽  
Two Component
Sign in / Sign up

Export Citation Format

Share Document