scholarly journals Analysis of the Activity and Regulon of the Two-Component Regulatory System Composed by Cjj81176_1484 and Cjj81176_1483 of Campylobacter jejuni

2015 ◽  
Vol 197 (9) ◽  
pp. 1592-1605 ◽  
Author(s):  
Paul M. Luethy ◽  
Steven Huynh ◽  
Craig T. Parker ◽  
David R. Hendrixson
Keyword(s):  
Campylobacter Jejuni ◽  
Histidine Kinase ◽  
Intestinal Tract ◽  
Diarrheal Disease ◽  
Response Regulator ◽  
Optimal Growth ◽  
Content Type ◽  
Regulatory Systems ◽  
Two Component ◽  
Genes Encoding

ABSTRACTCampylobacter jejuniis a leading cause of bacterial diarrheal disease and a frequent commensal of the intestinal tract in poultry and other animals. For optimal growth and colonization of hosts,C. jejuniemploys two-component regulatory systems (TCSs) to monitor environmental conditions and promote proper expression of specific genes. We analyzed the potential ofC. jejuniCjj81176_1484(Cjj1484) andCjj81176_1483(Cjj1483) to encode proteins of a cognate TCS that influences expression of genes possibly important forC. jejunigrowth and colonization. Transcriptome analysis revealed that the regulons of the Cjj81176_1484 (Cjj1484) histidine kinase and the Cjj81176_1483 (Cjj1483) response regulator contain many common genes, suggesting that these proteins likely form a cognate TCS. We found that this TCS generally functions to repress expression of specific proteins with roles in metabolism, iron/heme acquisition, and respiration. Furthermore, the TCS repressed expression ofCjj81176_0438andCjj81176_0439, which had previously been found to encode a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract. However, the TCS and other specific genes whose expression is repressed by the TCS were not required for colonization of chicks. We observed that the Cjj1483 response regulator binds target promoters in both unphosphorylated and phosphorylated forms and influences expression of some specific genes independently of the Cjj1484 histidine kinase. This work further expands the signaling mechanisms ofC. jejuniand provides additional insights regarding the complex and multifactorial regulation of many genes involved in basic metabolism, respiration, and nutrient acquisition that the bacterium requires for optimal growth in different environments.IMPORTANCEBacterial two-component regulatory systems (TCSs) link environmental cues to expression of specific genes that enable optimal bacterial growth or colonization of hosts. We found that theCampylobacter jejuniCjj1484 histidine kinase and Cjj1483 response regulator function as a cognate TCS to largely repress expression of target genes encoding a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract, as well as other genes encoding proteins for heme or iron acquisition, metabolism, and respiration. We also discovered different modes by which Cjj1483 may mediate repression with and without Cjj1484. This work provides insight into the signal transduction mechanisms of a leading cause of bacterial diarrheal disease and emphasizes the multifactorial and complex regulation of specific biological processes inC. jejuni.

scholarly journals The Hybrid Histidine Kinase Hk1 Is Part of a Two-Component System That Is Essential for Survival of Borrelia burgdorferi in Feeding Ixodes scapularis Ticks

2011 ◽  
Vol 79 (8) ◽  
pp. 3117-3130 ◽  
Author(s):  
Melissa J. Caimano ◽  
Melisha R. Kenedy ◽  
Toru Kairu ◽  
Daniel C. Desrosiers ◽  
Michael Harman ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Histidine Kinase ◽  
Ixodes Scapularis ◽  
Response Regulator ◽  
Content Type ◽  
Diguanylate Cyclases ◽  
Two Component ◽  
Tick Transmission ◽  
Two Component Systems ◽  
Hybrid Histidine Kinase

ABSTRACTTwo-component systems (TCS) are principal mechanisms by which bacteria adapt to their surroundings.Borrelia burgdorferiencodes only two TCS. One is comprised of a histidine kinase, Hk2, and the response regulator Rrp2. While the contribution of Hk2 remains unclear, Rrp2 is part of a regulatory pathway involving the spirochete's alternate sigma factors, RpoN and RpoS. Genes within the Rrp2/RpoN/RpoS regulon function to promote tick transmission and early infection. The other TCS consists of a hybrid histidine kinase, Hk1, and the response regulator Rrp1. Hk1 is composed of two periplasmic sensor domains (D1 and D2), followed by conserved cytoplasmic histidine kinase core, REC, and Hpt domains. In addition to its REC domain, Rrp1 contains a GGDEF motif characteristic of diguanylate cyclases. To investigate the role of Hk1 during the enzootic cycle, we inactivated this gene in two virulent backgrounds. Extensive characterization of the resulting mutants revealed a dramatic phenotype whereby Hk1-deficient spirochetes are virulent in mice and able to migrate out of the bite site during feeding but are killed within the midgut following acquisition. We hypothesize that the phosphorelay between Hk1 and Rrp1 is initiated by the binding of feeding-specific ligand(s) to Hk1 sensor domain D1 and/or D2. Once activated, Rrp1 directs the synthesis of cyclic dimeric GMP (c-di-GMP), which, in turn, modulates the expression and/or activity of gene products required for survival within feeding ticks. In contrast to the Rrp2/RpoN/RpoS pathway, which is active only within feeding nymphs, the Hk1/Rrp1 TCS is essential for survival during both larval and nymphal blood meals.

scholarly journals The Two-Component Signal Transduction System VxrAB Positively Regulates Vibrio cholerae Biofilm Formation

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Jennifer K. Teschler ◽  
Andrew T. Cheng ◽  
Fitnat H. Yildiz
Keyword(s):  
Signal Transduction ◽  
Vibrio Cholerae ◽  
Histidine Kinase ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Response Regulator ◽  
Systematic Analysis ◽  
Content Type ◽  
Two Component ◽  
Two Component Signal Transduction

ABSTRACT Two-component signal transduction systems (TCSs), typically composed of a sensor histidine kinase (HK) and a response regulator (RR), are the primary mechanism by which pathogenic bacteria sense and respond to extracellular signals. The pathogenic bacterium Vibrio cholerae is no exception and harbors 52 RR genes. Using in-frame deletion mutants of each RR gene, we performed a systematic analysis of their role in V. cholerae biofilm formation. We determined that 7 RRs impacted the expression of an essential biofilm gene and found that the recently characterized RR, VxrB, regulates the expression of key structural and regulatory biofilm genes in V. cholerae. vxrB is part of a 5-gene operon, which contains the cognate HK vxrA and three genes of unknown function. Strains carrying ΔvxrA and ΔvxrB mutations are deficient in biofilm formation, while the ΔvxrC mutation enhances biofilm formation. The overexpression of VxrB led to a decrease in motility. We also observed a small but reproducible effect of the absence of VxrB on the levels of cyclic di-GMP (c-di-GMP). Our work reveals a new function for the Vxr TCS as a regulator of biofilm formation and suggests that this regulation may act through key biofilm regulators and the modulation of cellular c-di-GMP levels. IMPORTANCE Biofilms play an important role in the Vibrio cholerae life cycle, providing protection from environmental stresses and contributing to the transmission of V. cholerae to the human host. V. cholerae can utilize two-component systems (TCS), composed of a histidine kinase (HK) and a response regulator (RR), to regulate biofilm formation in response to external cues. We performed a systematic analysis of V. cholerae RRs and identified a new regulator of biofilm formation, VxrB. We demonstrated that the VxrAB TCS is essential for robust biofilm formation and that this system may regulate biofilm formation via its regulation of key biofilm regulators and cyclic di-GMP levels. This research furthers our understanding of the role that TCSs play in the regulation of V. cholerae biofilm formation.

scholarly journals Fumarate Regulation of Gene Expression in Escherichia coli by the DcuSR (dcuSR Genes) Two-Component Regulatory System

1998 ◽  
Vol 180 (20) ◽  
pp. 5421-5425 ◽  
Author(s):  
Evelyn Zientz ◽  
Johannes Bongaerts ◽  
Gottfried Unden
Keyword(s):  
Escherichia Coli ◽  
Histidine Kinase ◽  
Response Regulator ◽  
Regulation Of Gene Expression ◽  
Regulatory System ◽  
E Coli ◽  
Expression In Escherichia Coli ◽  
Two Component ◽  
Genes Encoding ◽  
Periplasmic Domain

ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C4-dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previouslyyjdHG) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR anddcuS genes caused the loss of C4-dicarboxylate-stimulated synthesis of fumarate reductase (frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB (dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C4-dicarboxylate sensing. Regulation by DcuR and DcuS responded to the presence of the C4-dicarboxylates fumarate, succinate, malate, aspartate, tartrate, and maleate. Since maleate is not taken up by the bacteria under these conditions, the carboxylates presumably act from without. Genes of the aerobic C4-dicarboxylate pathway encoding succinate dehydrogenase (sdhCDAB) and the aerobic succinate carrier (dctA) are only marginally or negatively regulated by the DcuSR system. The CitAB two-component regulatory system, which is highly similar to DcuSR, had no effect on C4-dicarboxylate regulation of any of the genes.

scholarly journals Novel two-component regulatory systems play a role in biofilm formation of Lactobacillus reuteri rodent isolate 100-23

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 795-806 ◽  
Author(s):  
Marcia Shu-Wei Su ◽  
Michael G. Gänzle
Keyword(s):  
Histidine Kinase ◽  
Biofilm Formation ◽  
Lactobacillus Reuteri ◽  
Response Regulator ◽  
Multiple Genes ◽  
Regulatory Systems ◽  
Two Component ◽  
Two Component Systems ◽  
Processing Peptidase

This study characterized the two-component regulatory systems encoded by bfrKRT and cemAKR, and assessed their influence on biofilm formation by Lactobacillus reuteri 100-23. A method for deletion of multiple genes was employed to disrupt the genetic loci of two-component systems. The operons bfrKRT and cemAKR showed complementary organization. Genes bfrKRT encode a histidine kinase, a response regulator and an ATP-binding cassette-type transporter with a bacteriocin-processing peptidase domain, respectively. Genes cemAKR code for a signal peptide, a histidine kinase and a response regulator, respectively. Deletion of single or multiple genes in the operons bfrKRT and cemAKR did not affect cell morphology, growth or the sensitivity to various stressors. However, gene disruption affected biofilm formation; this effect was dependent on the carbon source. Deletion of bfrK or cemA increased sucrose-dependent biofilm formation in vitro. Glucose-dependent biofilm formation was particularly increased by deletion of cemK. The expression of cemK and cemR was altered by deletion of bfrK, indicating cross-talk between these two regulatory systems. These results may contribute to our understanding of the genetic factors related to the biofilm formation and competitiveness of L. reuteri in intestinal ecosystems.

scholarly journals Mutations Affecting HVO_1357 or HVO_2248 Cause Hypermotility in Haloferax volcanii, Suggesting Roles in Motility Regulation

Genes ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 58
Author(s):  
Michiyah Collins ◽  
Simisola Afolayan ◽  
Aime B. Igiraneza ◽  
Heather Schiller ◽  
Elise Krespan ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Response Regulator ◽  
Regulatory System ◽  
Haloferax Volcanii ◽  
Adjacent Gene ◽  
Transposon Insertion ◽  
Regulatory Systems ◽  
Two Component ◽  
Motility Regulation ◽  
Transposon Insertions

Motility regulation plays a key role in prokaryotic responses to environmental stimuli. Here, we used a motility screen and selection to isolate hypermotile Haloferax volcanii mutants from a transposon insertion library. Whole genome sequencing revealed that hypermotile mutants were predominantly affected in two genes that encode HVO_1357 and HVO_2248. Alterations of these genes comprised not only transposon insertions but also secondary genome alterations. HVO_1357 contains a domain that was previously identified in the regulation of bacteriorhodopsin transcription, as well as other domains frequently found in two-component regulatory systems. The genes adjacent to hvo_1357 encode a sensor box histidine kinase and a response regulator, key players of a two-component regulatory system. None of the homologues of HVO_2248 have been characterized, nor does it contain any of the assigned InterPro domains. However, in a significant number of Haloferax species, the adjacent gene codes for a chemotaxis receptor/transducer. Our results provide a foundation for characterizing the root causes underlying Hfx. volcanii hypermotility.

scholarly journals A Regulatory Checkpoint during Flagellar Biogenesis in Campylobacter jejuni Initiates Signal Transduction To Activate Transcription of Flagellar Genes

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Joseph M. Boll ◽  
David R. Hendrixson
Keyword(s):  
Signal Transduction ◽  
Campylobacter Jejuni ◽  
Gene Transcription ◽  
Type Iii Secretion ◽  
Secretion System ◽  
Flagellar Gene ◽  
Content Type ◽  
Regulatory Systems ◽  
Two Component ◽  
Flagellar Biogenesis

ABSTRACTMany polarly flagellated bacteria require similar two-component regulatory systems (TCSs) and σ54to activate transcription of genes essential for flagellar motility. Herein, we discovered that in addition to the flagellar type III secretion system (T3SS), theCampylobacter jejuniflagellar MS ring and rotor are required to activate the FlgSR TCS. Mutants lacking the FliF MS ring and FliG C ring rotor proteins were as defective as T3SS mutants in FlgSR- and σ54-dependent flagellar gene expression. Also, FliF and FliG required each other for stability, which is mediated by atypical extensions to the proteins. A FliF mutant that presumably does not interact with the T3SS protein FlhA did not support flagellar gene transcription, suggesting that FliF-T3SS interactions are essential to generate a signal sensed by the cytoplasmic FlgS histidine kinase. Furthermore, the flagellar T3SS was required for FlgS to immunoprecipitate with FliF and FliG. We propose a model whereby the flagellar T3SS facilitates FliF and FliG multimerization into the MS ring and rotor. As a result, these flagellar structures form a cytoplasmic complex that interacts with and is sensed by FlgS. The synthesis of these structures appears to be a regulatory checkpoint in flagellar biogenesis that the FlgS kinase monitors to initiate signal transduction that activates σ54and expression of genes required for the next stage of flagellation. Given that other polar flagellates have flagellar transcriptional hierarchies that are organized similarly as inC. jejuni, this regulatory checkpoint may exist in a broad range of bacteria to influence similar TCSs and flagellar gene transcription.IMPORTANCEDespite the presence of numerous two-component regulatory systems (TCSs) in bacteria, direct signals sensed by TCSs to activate signal transduction are known for only a minority. Polar flagellates, includingPseudomonas,Vibrio,Helicobacter, andCampylobacterspecies, require a similar TCS and σ54for flagellar gene transcription, but the activating signals for these TCSs are unknown. We explored signals that activate theCampylobacter jejuniFlgSR TCS to initiate σ54-dependent flagellar gene transcription. Our discoveries suggest that the FlgS histidine kinase monitors the formation of the flagellar type III secretion system and the surrounding MS and C rings. The synthesis of these structures creates a regulatory checkpoint in flagellar biogenesis that is sensed by FlgS to ensure proper transcription of the next set of genes for subsequent steps in flagellation. Given the conservation of flagellar-associated TCSs and transcriptional cascades in polar flagellates, this regulatory checkpoint in flagellar biogenesis likely impacts flagellation in a broad range of bacteria.

scholarly journals Activation of Bvg-Repressed Genes in Bordetella pertussis by RisA Requires Cross Talk from Noncooperonic Histidine Kinase RisK

2017 ◽  
Vol 199 (22) ◽  
Author(s):  
Qing Chen ◽  
Victoria Ng ◽  
Jason M. Warfel ◽  
Tod J. Merkel ◽  
Scott Stibitz
Keyword(s):  
Bordetella Pertussis ◽  
Histidine Kinase ◽  
Genomic Sequence ◽  
Response Regulator ◽  
Two Component System ◽  
Kinase Gene ◽  
Content Type ◽  
Reading Frame ◽  
Two Component

ABSTRACT The two-component response regulator RisA, encoded by open reading frame BP3554 in the Bordetella pertussis Tohama I genomic sequence, is a known activator of vrg genes, a set of genes whose expression is increased under the same environmental conditions (known as modulation) that result in repression of the bvgAS virulence regulon. Here we demonstrate that RisA is phosphorylated in vivo and that RisA phosphorylation is required for activation of vrg genes. An adjacent histidine kinase gene, risS, is truncated by frameshift mutation in B. pertussis but not in Bordetella bronchiseptica or Bordetella parapertussis. Neither deletion of risS′ or bvgAS nor phenotypic modulation with MgSO4 affected levels of phosphorylated RisA (RisA∼P) in B. pertussis. However, RisA phosphorylation did require the histidine kinase encoded by BP3223, here named RisK (cognate histidine kinase of RisA). RisK was also required for expression of the vrg genes. This requirement could be obviated by the introduction of the phosphorylation-mimicking RisAD60E mutant, indicating that an active conformation of RisA, but not phosphorylation per se, is crucial for vrg activation. Interestingly, expression of vrg genes is still modulated by MgSO4 in cells harboring the RisAD60E mutation, suggesting that the activated RisA senses additional signals to control vrg expression in response to environmental stimuli. IMPORTANCE In B. pertussis, the BvgAS two-component system activates the expression of virulence genes by binding of BvgA∼P to their promoters. Expression of the reciprocally regulated vrg genes requires RisA and is also repressed by the Bvg-activated BvgR. RisA is an OmpR-like response regulator, but RisA phosphorylation was not expected because the gene for its presumed, cooperonic, histidine kinase is inactivated by mutation. In this study, we demonstrate phosphorylation of RisA in vivo by a noncooperonic histidine kinase. We also show that RisA phosphorylation is necessary but not sufficient for vrg activation but, importantly, is not affected by BvgAS status. Instead, we propose that vrg expression is controlled by BvgAS through its regulation of BvgR, a cyclic di-GMP (c-di-GMP) phosphodiesterase.

scholarly journals Orphan Hybrid Histidine Protein Kinase SinK Acts as a Signal Integrator To Fine-Tune Multicellular Behavior inMyxococcus xanthus

2019 ◽  
Vol 201 (6) ◽  
Author(s):  
Maike M. Glaser ◽  
Penelope I. Higgs
Keyword(s):  
Environmental Conditions ◽  
Histidine Kinase ◽  
Response Regulator ◽  
Myxococcus Xanthus ◽  
Histidine Kinases ◽  
Content Type ◽  
Environmental Bacterium ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Fine Tune

ABSTRACTHis-Asp phosphorelay (also known as two-component signal transduction) proteins are the predominant mechanism used in most bacteria to control behavior in response to changing environmental conditions. In addition to systems consisting of a simple two-component system utilizing an isolated histidine kinase/response regulator pair, some bacteria are enriched in histidine kinases that serve as signal integration proteins; these kinases are usually characterized by noncanonical domain architecture, and the responses that they regulate may be difficult to identify. The environmental bacteriumMyxococcus xanthusis highly enriched in these noncanonical histidine kinases.M. xanthusis renowned for a starvation-induced multicellular developmental program in which some cells are induced to aggregate into fruiting bodies and then differentiate into environmentally resistant spores. Here, we characterize theM. xanthusorphan hybrid histidine kinase SinK (Mxan_4465), which consists of a histidine kinase transmitter followed by two receiver domains (REC1and REC2). NonphosphorylatablesinKmutants were analyzed under two distinct developmental conditions and using a new high-resolution developmental assay. These assays revealed that SinK autophosphorylation and REC1impact the onset of aggregation and/or the mobility of aggregates, while REC2impacts sporulation efficiency. SinK activity is controlled by a genus-specific hypothetical protein (SinM; Mxan_4466). We propose that SinK serves to fine-tune fruiting body morphology in response to environmental conditions.IMPORTANCEBiofilms are multicellular communities of microorganisms that play important roles in host disease or environmental biofouling. Design of preventative strategies to block biofilms depends on understanding the molecular mechanisms used by microorganisms to build them. The production of biofilms in bacteria often involves two-component signal transduction systems in which one protein component (a kinase) detects an environmental signal and, through phosphotransfer, activates a second protein component (a response regulator) to change the transcription of genes necessary to produce a biofilm. We show that an atypical kinase, SinK, modulates several distinct stages of specialized biofilm produced by the environmental bacteriumMyxococcus xanthus. SinK likely integrates multiple signals to fine-tune biofilm formation in response to distinct environmental conditions.

scholarly journals Activation of the Campylobacter jejuni FlgSR Two-Component System Is Linked to the Flagellar Export Apparatus

2009 ◽  
Vol 191 (8) ◽  
pp. 2656-2667 ◽  
Author(s):  
Stephanie N. Joslin ◽  
David R. Hendrixson
Keyword(s):  
Gene Expression ◽  
Campylobacter Jejuni ◽  
Response Regulator ◽  
Regulatory System ◽  
Two Component System ◽  
Regulatory Cascade ◽  
Regulatory Systems ◽  
Two Component ◽  
Flagellar Protein ◽  
Flagellar Genes

ABSTRACT Activation of σ54-dependent gene expression essential for formation of flagella in Campylobacter jejuni requires the components of the inner membrane-localized flagellar export apparatus and the FlgSR two-component regulatory system. In this study, we characterized the FlgS sensor kinase and how activation of the protein is linked to the flagellar export apparatus. We found that FlgS is localized to the C. jejuni cytoplasm and that His141 of FlgS is essential for autophosphorylation, phosphorelay to the cognate FlgR response regulator, motility, and expression of σ54-dependent flagellar genes. Mutants with incomplete flagellar export apparatuses produced wild-type levels of FlgS and FlgR, but they were defective for signaling through the FlgSR system. By using genetic approaches, we found that FlgSR activity is linked to and downstream of the flagellar export apparatus in a regulatory cascade that terminates in expression of σ54-dependent flagellar genes. By analyzing defined flhB and fliI mutants of C. jejuni that form flagellar export apparatuses that are secretion incompetent, we determined that formation of the apparatus is required to contribute to the signal sensed by FlgS to terminate in activation of expression of σ54-dependent flagellar genes. Considering that the flagellar export apparatuses of Escherichia coli and Salmonella species influence σ28-dependent flagellar gene expression, our work expands the signaling activity of the apparatuses to include σ54-dependent pathways of C. jejuni and possibly other motile bacteria. This study indicates that these apparatuses have broader functions beyond flagellar protein secretion, including activation of essential two-component regulatory systems required for expression of σ54-dependent flagellar genes.

scholarly journals A Novel Campylobacter jejuniTwo-Component Regulatory System Important for Temperature-Dependent Growth and Colonization

1999 ◽  
Vol 181 (10) ◽  
pp. 3298-3302 ◽  
Author(s):  
Ana M. Brás ◽  
Shimonti Chatterjee ◽  
Brendan W. Wren ◽  
Diane G. Newell ◽  
Julian M. Ketley
Keyword(s):  
Intestinal Tract ◽  
Diarrheal Disease ◽  
Response Regulator ◽  
Protein Profile ◽  
Regulatory System ◽  
Growth Characteristics ◽  
Regulator Gene ◽  
Temperature Dependent ◽  
Two Component ◽  
Dependent Growth

ABSTRACT Campylobacter jejuni colonizes the intestines of domestic and wild animals and is a common cause of human diarrheal disease. We identified a two-component regulatory system, designated the RacR-RacS (reduced ability to colonize) system, that is involved in a temperature-dependent signalling pathway. A mutation of the response regulator gene racR reduced the organism’s ability to colonize the chicken intestinal tract and resulted in temperature-dependent changes in its protein profile and growth characteristics.

Sign in / Sign up

Export Citation Format

Share Document