scholarly journals A Conserved Two-Component Signal Transduction System Controls the Response to Phosphate Starvation in Bifidobacterium breve UCC2003

2012 ◽  
Vol 78 (15) ◽  
pp. 5258-5269 ◽  
Author(s):  
Pablo Alvarez-Martin ◽  
Matilde Fernández ◽  
Mary O'Connell-Motherway ◽  
Kerry Joan O'Connell ◽  
Nicolas Sauvageot ◽  
...  
Keyword(s):  
Response Regulator ◽  
Regulatory Protein ◽  
Gc Content ◽  
Regulatory System ◽  
Bioinformatic Analysis ◽  
Insertion Mutant ◽  
Recognition Sequence ◽  
Content Type ◽  
Bifidobacterium Breve ◽  
Two Component

ABSTRACTThis work reports on the identification and molecular characterization of the two-component regulatory system (2CRS) PhoRP, which controls the response to inorganic phosphate (Pi) starvation inBifidobacterium breveUCC2003. The response regulator PhoP was shown to bind to the promoter region ofpstSCAB, specifying a predicted Pitransporter system, as well as that ofphoU, which encodes a putative Pi-responsive regulatory protein. This interaction is assumed to cause transcriptional modulation under conditions of Pilimitation. Our data suggest that thephoRPgenes are subject to positive autoregulation and, together withpstSCABand presumablyphoU, represent the complete regulon controlled by thephoRP-encoded 2CRS inB. breveUCC2003. Determination of the minimal PhoP binding region combined with bioinformatic analysis revealed the probable recognition sequence of PhoP, designated here as the PHO box, which together withphoRPis conserved among many high-GC-content Gram-positive bacteria. The importance of thephoRP2CRS in the response ofB. breveto Pistarvation conditions was confirmed by analysis of aB. brevephoPinsertion mutant which exhibited decreased growth under phosphate-limiting conditions compared to its parent strain UCC2003.

scholarly journals A Two-Component Regulatory System Controls Autoregulated Serpin Expression in Bifidobacterium breve UCC2003

2012 ◽  
Vol 78 (19) ◽  
pp. 7032-7041 ◽  
Author(s):  
Pablo Alvarez-Martin ◽  
Mary O'Connell Motherway ◽  
Francesca Turroni ◽  
Elena Foroni ◽  
Marco Ventura ◽  
...  
Keyword(s):  
Response Regulator ◽  
Regulatory System ◽  
Site Directed Mutagenesis ◽  
Insertion Mutant ◽  
Recognition Sequence ◽  
Mobility Shift ◽  
Content Type ◽  
Bifidobacterium Breve ◽  
Two Component

ABSTRACTThis work reports on the identification and molecular characterization of a two-component regulatory system (2CRS), encoded byserRK, which is believed to control the expression of theser2003locus inBifidobacterium breveUCC2003. Theser2003locus consists of two genes, Bbr_1319 (sagA) and Bbr_1320 (serU), which are predicted to encode a hypothetical membrane-associated protein and a serpin-like protein, respectively. The response regulator SerR was shown to bind to the promoter region ofser2003, and the probable recognition sequence of SerR was determined by a combinatorial approach ofin vitrosite-directed mutagenesis coupled to transcriptional fusion and electrophoretic mobility shift assays (EMSAs). The importance of theserRK2CRS in the response ofB. breveto protease-mediated induction was confirmed by generating aB. breve serRinsertion mutant, which was shown to exhibit alteredser2003transcriptional induction patterns compared to the parent strain, UCC2003. Interestingly, the analysis of aB. breve serUmutant revealed that the SerRK signaling pathway appears to include a SerU-dependent autoregulatory loop.

scholarly journals Identification of a Second Two-Component Signal Transduction System That Controls Fosfomycin Tolerance and Glycerol-3-Phosphate Uptake

2014 ◽  
Vol 197 (5) ◽  
pp. 861-871 ◽  
Author(s):  
Kumiko Kurabayashi ◽  
Yuko Hirakawa ◽  
Koichi Tanimoto ◽  
Haruyoshi Tomita ◽  
Hidetada Hirakawa
Keyword(s):  
Phosphate Uptake ◽  
Response Regulator ◽  
Anaerobic Respiration ◽  
Regulatory System ◽  
Carbon Substrate ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Biological Cost

Particular interest in fosfomycin has resurfaced because it is a highly beneficial antibiotic for the treatment of refractory infectious diseases caused by pathogens that are resistant to other commonly used antibiotics. The biological cost to cells of resistance to fosfomycin because of chromosomal mutation is high. We previously found that a bacterial two-component system, CpxAR, induces fosfomycin tolerance in enterohemorrhagicEscherichia coli(EHEC) O157:H7. This mechanism does not rely on irreversible genetic modification and allows EHEC to relieve the fitness burden that results from fosfomycin resistance in the absence of fosfomycin. Here we show that another two-component system, TorSRT, which was originally characterized as a regulatory system for anaerobic respiration utilizing trimethylamine-N-oxide (TMAO), also induces fosfomycin tolerance. Activation of the Tor regulatory pathway by overexpression oftorR, which encodes the response regulator, or addition of TMAO increased fosfomycin tolerance in EHEC. We also show that phosphorylated TorR directly represses the expression ofglpT, a gene that encodes a symporter of fosfomycin and glycerol-3-phosphate, and activation of the TorR protein results in the reduced uptake of fosfomycin by cells. However, cells in which the Tor pathway was activated had an impaired growth phenotype when cultured with glycerol-3-phosphate as a carbon substrate. These observations suggest that the TorSRT pathway is the second two-component system to reversibly control fosfomycin tolerance and glycerol-3-phosphate uptake in EHEC, and this may be beneficial for bacteria by alleviating the biological cost. We expect that this mechanism could be a potential target to enhance the utility of fosfomycin as chemotherapy against multidrug-resistant pathogens.

scholarly journals RocA Binds CsrS To Modulate CsrRS-Mediated Gene Regulation in Group A Streptococcus

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Nicola N. Lynskey ◽  
Jorge J. Velarde ◽  
Meredith B. Finn ◽  
Simon L. Dove ◽  
Michael R. Wessels
Keyword(s):  
Gene Regulation ◽  
Target Genes ◽  
Response Regulator ◽  
Critical Role ◽  
Regulatory Protein ◽  
Regulatory System ◽  
Fine Tuning ◽  
Human Pathogen ◽  
Two Component ◽  
Group A

ABSTRACT The orphan regulator RocA plays a critical role in the colonization and pathogenesis of the obligate human pathogen group A Streptococcus. Despite multiple lines of evidence supporting a role for RocA as an auxiliary regulator of the control of virulence two-component regulatory system CsrRS (or CovRS), the mechanism of action of RocA remains unknown. Using a combination of in vitro and in vivo techniques, we now find that RocA interacts with CsrS in the streptococcal membrane via its N-terminal region, which contains seven transmembrane domains. This interaction is essential for RocA-mediated regulation of CsrRS function. Furthermore, we demonstrate that RocA forms homodimers via its cytoplasmic domain. The serotype-specific RocA truncation in M3 isolates alters this homotypic interaction, resulting in protein aggregation and impairment of RocA-mediated regulation. Taken together, our findings provide insight into the molecular requirements for functional interaction of RocA with CsrS to modulate CsrRS-mediated gene regulation. IMPORTANCE Bacterial two-component regulatory systems, comprising a membrane-bound sensor kinase and cytosolic response regulator, are critical in coordinating the bacterial response to changing environmental conditions. More recently, auxiliary regulators which act to modulate the activity of two-component systems, allowing integration of multiple signals and fine-tuning of bacterial responses, have been identified. RocA is a regulatory protein encoded by all serotypes of the important human pathogen group A Streptococcus. Although RocA is known to exert its regulatory activity via the streptococcal two-component regulatory system CsrRS, the mechanism by which it functions was unknown. Based on new experimental evidence, we propose a model whereby RocA interacts with CsrS in the streptococcal cell membrane to enhance CsrS autokinase activity and subsequent phosphotransfer to the response regulator CsrR, which mediates transcriptional repression of target genes.

scholarly journals Polymyxin B Resistance and Biofilm Formation in Vibrio cholerae Are Controlled by the Response Regulator CarR

2015 ◽  
Vol 83 (3) ◽  
pp. 1199-1209 ◽  
Author(s):  
Kivanc Bilecen ◽  
Jiunn C. N. Fong ◽  
Andrew Cheng ◽  
Christopher J. Jones ◽  
David Zamorano-Sánchez ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Lipid A ◽  
Response Regulator ◽  
Regulatory Region ◽  
Regulatory System ◽  
Polymyxin B ◽  
Content Type ◽  
Two Component ◽  
Antimicrobial Peptide Resistance

Two-component systems play important roles in the physiology of many bacterial pathogens.Vibrio cholerae's CarRS two-component regulatory system negatively regulates expression ofvps(Vibriopolysaccharide) genes and biofilm formation. In this study, we report that CarR confers polymyxin B resistance by positively regulating expression of thealmEFGgenes, whose products are required for glycine and diglycine modification of lipid A. We determined that CarR directly binds to the regulatory region of thealmEFGoperon. Similarly to acarRmutant, strains lackingalmE,almF, andalmGexhibited enhanced polymyxin B sensitivity. We also observed that strains lackingalmEor thealmEFGoperon have enhanced biofilm formation. Our results reveal that CarR regulates biofilm formation and antimicrobial peptide resistance inV. cholerae.

scholarly journals Genome-Wide Identification of Genes Necessary for Biofilm Formation by Nosocomial Pathogen Stenotrophomonas maltophilia Reveals that Orphan Response Regulator FsnR Is a Critical Modulator

2014 ◽  
Vol 81 (4) ◽  
pp. 1200-1209 ◽  
Author(s):  
Xiu-Min Kang ◽  
Fang-Fang Wang ◽  
Huan Zhang ◽  
Qi Zhang ◽  
Wei Qian
Keyword(s):  
Cell Motility ◽  
Biofilm Formation ◽  
Stenotrophomonas Maltophilia ◽  
Response Regulator ◽  
Critical Role ◽  
Regulatory Protein ◽  
Lipid Synthesis ◽  
Cell Aggregation ◽  
Insertion Mutant ◽  
Content Type

ABSTRACTStenotrophomonas maltophiliais a Gram-negative bacterial pathogen of increasing concern to human health. Most clinical isolates ofS. maltophiliaefficiently form biofilms on biotic and abiotic surfaces, making this bacterium resistant to a number of antibiotic treatments and therefore difficult to eliminate. To date, very few studies have investigated the molecular and regulatory mechanisms responsible forS. maltophiliabiofilm formation. Here we constructed a random transposon insertion mutant library ofS. maltophiliaATCC 13637 and screened 14,028 clones. A total of 46 nonredundant genes were identified. Mutants of these genes exhibited marked changes in biofilm formation, suggesting that multiple physiological pathways, including extracellular polysaccharide production, purine synthesis, transportation, and peptide and lipid synthesis, are involved in bacterial cell aggregation. Of these genes, 20 putatively contributed to flagellar biosynthesis, indicating a critical role for cell motility inS. maltophiliabiofilm formation. Genetic and biochemical evidence demonstrated that an orphan response regulator, FsnR, activated transcription of at least two flagellum-associated operons by directly binding to their promoters. This regulatory protein plays a fundamental role in controlling flagellar assembly, cell motility, and biofilm formation. These results provide a genetic basis to systematically study biofilm formation ofS. maltophilia.

scholarly journals Characterization of a Four-Component Regulatory System Controlling Bacteriocin Production in Streptococcus gallolyticus

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alexis Proutière ◽  
Laurence du Merle ◽  
Bruno Périchon ◽  
Hugo Varet ◽  
Myriam Gominet ◽  
...  
Keyword(s):  
Response Regulator ◽  
Regulatory System ◽  
Opportunistic Pathogen ◽  
Bacteriocin Production ◽  
Two Component System ◽  
Promoter Regions ◽  
Component System ◽  
Content Type ◽  
Streptococcus Gallolyticus ◽  
Two Component

ABSTRACT Bacteriocins are natural antimicrobial peptides produced by bacteria to kill closely related competitors. The opportunistic pathogen Streptococcus gallolyticus subsp. gallolyticus was recently shown to outcompete commensal enterococci of the murine microbiota under tumoral conditions thanks to the production of a two-peptide bacteriocin named gallocin. Here, we identified four genes involved in the regulatory control of gallocin in S. gallolyticus subsp. gallolyticus UCN34 that encode a histidine kinase/response regulator two-component system (BlpH/BlpR), a secreted peptide (GSP [gallocin-stimulating peptide]), and a putative regulator of unknown function (BlpS). While BlpR is a typical 243-amino-acid (aa) response regulator possessing a phospho-receiver domain and a LytTR DNA-binding domain, BlpS is a 108-aa protein containing only a LytTR domain. Our results showed that the secreted peptide GSP activates the dedicated two-component system BlpH/BlpR to induce gallocin transcription. A genome-wide transcriptome analysis indicates that this regulatory system (GSP-BlpH/BlpR) is specific for bacteriocin production. Importantly, as opposed to BlpR, BlpS was shown to repress gallocin gene transcription. A conserved operator DNA sequence of 30 bp was found in all promoter regions regulated by BlpR and BlpS. Electrophoretic mobility shift assays (EMSA) and footprint assays showed direct and specific binding of BlpS and BlpR to various regulated promoter regions in a dose-dependent manner on this conserved sequence. Gallocin expression appears to be tightly controlled in S. gallolyticus subsp. gallolyticus by quorum sensing and antagonistic activity of 2 LytTR-containing proteins. Competition experiments in gut microbiota medium and 5% CO2 to mimic intestinal conditions demonstrate that gallocin is functional under these in vivo-like conditions. IMPORTANCE Streptococcus gallolyticus subsp. gallolyticus, formerly known as Streptococcus bovis biotype I, is an opportunistic pathogen causing septicemia and endocarditis in the elderly often associated with asymptomatic colonic neoplasia. Recent studies indicate that S. gallolyticus subsp. gallolyticus is both a driver and a passenger of colorectal cancer. We previously showed that S. gallolyticus subsp. gallolyticus produces a bacteriocin, termed gallocin, enabling colonization of the colon under tumoral conditions by outcompeting commensal members of the murine microbiota such as Enterococcus faecalis. Here, we identified and extensively characterized a four-component system that regulates gallocin production. Gallocin gene transcription is activated by a secreted peptide pheromone (GSP) and a two-component signal transduction system composed of a transmembrane histidine kinase receptor (BlpH) and a cytosolic response regulator (BlpR). Finally, a DNA-binding protein (BlpS) was found to repress gallocin genes transcription, likely by antagonizing BlpR. Understanding gallocin regulation is crucial to prevent S. gallolyticus subsp. gallolyticus colon colonization under tumoral conditions.

scholarly journals Transcription Analysis of a Lantibiotic Gene Cluster from Bifidobacterium longum DJO10A

2011 ◽  
Vol 77 (17) ◽  
pp. 5879-5887 ◽  
Author(s):  
Ju-Hoon Lee ◽  
Xiulan Li ◽  
Daniel J. O'Sullivan
Keyword(s):  
Gene Expression ◽  
Response Regulator ◽  
Bifidobacterium Longum ◽  
Regulatory System ◽  
Broth Culture ◽  
Northern Hybridization ◽  
Transcription Start ◽  
Transcription Analysis ◽  
Content Type ◽  
Two Component

ABSTRACTBifidobacterium longumDJO10A was previously demonstrated to produce a lantibiotic, but only during growth on agar media. To evaluate the feasibility of production of this lantibiotic in broth media, a transcription analysis of thelanAgene was undertaken. Comparative microarray analysis of broth and agar cultures ofB. longumDJO10A revealed that the lantibiotic production, modification, transport/peptidase, and immunity genes were significantly upregulated in agar cultures, while the two-component regulatory genes were expressed equally under both conditions. This suggested that the signal transduction regulatory system should function in broth cultures. Real-time PCR and Northern hybridization confirmed thatlanAgene expression was significantly repressed in broth cultures. A crude lantibiotic preparation from an agar-grown culture was obtained, and its antimicrobial spectrum analysis revealed a broad inhibition range. Addition of this extract to broth cultures ofB. longumDJO10A inducedlanAgene expression in a dose-dependent fashion. Subinoculation using >10% of an induced broth culture maintainedlanAexpression. The expression oflanAwas log-phase specific, being significantly downregulated in stationary phase. Transcription start analysis oflanArevealed a 284-bp 5′ untranslated region, which was proposed to be involved in repression of transcription, while an inverted repeat structure located at bp −75 relative to the transcription start was strategically located to likely function as a binding site for the two-component response regulator. Understanding the transcription regulation of thislanAgene is the first step toward enabling production of this novel and potentially interesting lantibiotic in broth cultures.

scholarly journals Regulation of Sporangium Formation, Spore Dormancy, and Sporangium Dehiscence by a Hybrid Sensor Histidine Kinase in Actinoplanes missouriensis: Relationship with the Global Transcriptional Regulator TcrA

2020 ◽  
Vol 202 (21) ◽  
Author(s):  
Yuichiro Hashiguchi ◽  
Takeaki Tezuka ◽  
Yoshihiro Mouri ◽  
Kenji Konishi ◽  
Azusa Fujita ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Deletion Mutant ◽  
Response Regulator ◽  
Regulatory System ◽  
Morphological Development ◽  
Sequencing Analysis ◽  
Content Type ◽  
Rare Actinomycetes ◽  
Two Component ◽  
Hybrid Histidine Kinase

ABSTRACT The rare actinomycete Actinoplanes missouriensis forms terminal sporangia containing a few hundred flagellated spores. In response to water, the sporangia open and release the spores into external environments. The orphan response regulator TcrA functions as a global transcriptional activator during sporangium formation and dehiscence. Here, we report the characterization of an orphan hybrid histidine kinase, HhkA. Sporangia of an hhkA deletion mutant contained many distorted or ectopically germinated spores and scarcely opened to release the spores under sporangium dehiscence-inducing conditions. These phenotypic changes are quite similar to those observed in a tcrA deletion mutant. Comparative RNA sequencing analysis showed that genes controlled by HhkA mostly overlap TcrA-regulated genes. The direct interaction between HhkA and TcrA was suggested by a bacterial two-hybrid assay, but this was not conclusive. The phosphorylation of TcrA using acetyl phosphate as a phosphate donor markedly enhanced its affinity for the TcrA box sequences in the electrophoretic mobility shift assay. Taking these observations together with other results, we proposed that HhkA and TcrA compose a cognate two-component regulatory system, which controls the transcription of the genes involved in many aspects of morphological development, including sporangium formation, spore dormancy, and sporangium dehiscence in A. missouriensis. IMPORTANCE Actinoplanes missouriensis goes through complex morphological differentiation, including formation of flagellated spore-containing sporangia, sporangium dehiscence, swimming of zoospores, and germination of zoospores to filamentous growth. Although the orphan response regulator TcrA globally activates many genes required for sporangium formation, spore dormancy, and sporangium dehiscence, its partner histidine kinase remained unknown. Here, we analyzed the function of an orphan hybrid histidine kinase, HhkA, and proposed that HhkA constitutes a cognate two-component regulatory system with TcrA. That HhkA and TcrA homologues are highly conserved among the genus Actinoplanes and several closely related rare actinomycetes indicates that this possible two-component regulatory system is employed for complex morphological development in sporangium- and/or zoospore-forming rare actinomycetes.

scholarly journals Molecular Mechanisms of Phosphate Stress Activation of Pseudomonas aeruginosa Quorum Sensing Systems

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Xianfa Meng ◽  
Stephen Dela Ahator ◽  
Lian-Hui Zhang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Response Regulator ◽  
Regulatory System ◽  
Regulatory Genes ◽  
Phosphate Deficiency ◽  
Content Type ◽  
Sensing Systems ◽  
Two Component ◽  
Phosphate Depletion

ABSTRACT The hierarchical quorum sensing (QS) systems of Pseudomonas aeruginosa, consisting of las, pqs, and rhl, coordinate the expression of bacterial virulence genes. Previous studies showed that under phosphate deficiency conditions, two-component regulatory system PhoRB could activate various genes involved in cytotoxicity through modulation of QS systems, but the mechanism by which PhoR/PhoB influences QS remains largely unknown. Here, we provide evidence that among the key QS regulatory genes in P. aeruginosa, rhlR, pqsA, mvfR, and lasI were activated by the response regulator PhoB under phosphate-depleted conditions. We show that PhoB is a strong competitor against LasR and RsaL for binding to the promoter of lasI and induces significant expression of lasI, rhlR, and mvfR. However, expression of lasI, encoding the signal 3-oxo-C12-HSL, was increased only marginally under the same phosphate-depleted conditions. This seeming inconsistency was attributed to the induction of pvdQ, which encodes an enzyme for degradation of 3-oxo-C12-HSL signal molecules. Taken together, the results from this study demonstrate that through the two-component regulatory system PhoR/PhoB, phosphate depletion stress could influence the QS network by modulating several key regulators, including lasI, rhlR, mvfR, and pvdQ. The findings highlight not only the potency of the PhoR/PhoB-mediated bacterial stress response mechanism but also the plasticity of the P. aeruginosa QS systems in coping with the changed environmental conditions. IMPORTANCE It is not fully understood how phosphate deficiency could influence the virulence of Pseudomonas aeruginosa through modulation of the bacterial QS systems. This report presents a systemic investigation on the impact of phosphate depletion on the hierarchy of quorum sensing systems of P. aeruginosa. The results showed that phosphate stress could have an extensive impact on the QS networks of this bacterial pathogen. Among the 7 QS regulatory genes representing the 3 sets of QS systems tested, 4 were significantly upregulated by phosphate depletion stress through the PhoR/PhoB two-component regulatory system, especially the upstream QS regulatory gene lasI. We also present evidence that the response regulator PhoB was a strong competitor against the las regulators LasR and RsaL for the lasI promoter, unveiling the mechanistic basis of the process by which phosphate stress could modulate the bacterial QS systems.

AgmR controls transcription of a regulon with several operons essential for ethanol oxidation in Pseudomonas aeruginosa ATCC 17933

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1851-1857 ◽  
Author(s):  
Nicole Gliese ◽  
Viola Khodaverdi ◽  
Max Schobert ◽  
Helmut Görisch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ethanol Oxidation ◽  
Response Regulator ◽  
Regulatory System ◽  
Pyrroloquinoline Quinone ◽  
Kanamycin Resistance ◽  
Kanamycin Resistance Cassette ◽  
Two Component ◽  
Ethanol Dehydrogenase ◽  
Oxidation System

The response regulator AgmR was identified to be involved in the regulation of the quinoprotein ethanol oxidation system of Pseudomonas aeruginosa ATCC 17933. Interruption of the agmR gene by insertion of a kanamycin-resistance cassette resulted in mutant NG3, unable to grow on ethanol. After complementation with the intact agmR gene, growth on ethanol was restored. Transcriptional lacZ fusions were used to identify four operons which are regulated by the AgmR protein: the exaA operon encodes the pyrroloquinoline quinone (PQQ)-dependent ethanol dehydrogenase, the exaBC operon encodes a soluble cytochrome c 550 and an aldehyde dehydrogenase, the pqqABCDE operon carries the PQQ biosynthetic genes, and operon exaDE encodes a two-component regulatory system which controls transcription of the exaA operon. Transcription of exaA was restored by transformation of NG3 with a pUCP20T derivative carrying the exaDE genes under lac-promoter control. These data indicate that the AgmR response regulator and the exaDE two-component regulatory system are organized in a hierarchical manner. Gene PA1977, which appears to form an operon with the agmR gene, was found to be non-essential for growth on ethanol.

Sign in / Sign up

Export Citation Format

Share Document