scholarly journals The Response Regulator CroR Modulates Expression of the Secreted Stress-Induced SalB Protein in Enterococcus faecalis

2006 ◽  
Vol 188 (7) ◽  
pp. 2636-2645 ◽  
Author(s):  
Cécile Muller ◽  
Yoann Le Breton ◽  
Thierry Morin ◽  
Abdellah Benachour ◽  
Yanick Auffray ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Promoter Region ◽  
Response Regulator ◽  
Signal Transduction System ◽  
Promoter Regions ◽  
Mobility Shift ◽  
Dnase I Footprinting ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Electrophoretic Mobility Shift Assays

ABSTRACT The Enterococcus faecalis two-component signal transduction system CroRS, also referred as the RR-HK05 pair, is required for intrinsic β-lactam resistance (Y. R. Comenge, R. Quintiliani, Jr., L. Li, L. Dubost, J. P. Brouard, J. E. Hugonnet, and M. Arthur, J. Bacteriol. 185:7184-7192, 2003) and is also suspected to be involved in the expression of salB (previously referred to as sagA), a gene important for resistance to environmental stress and cell morphology (Y. Le Breton, G. Boël, A. Benachour, H. Prévost, Y. Auffray, and A. Rincé, Environ. Microbiol. 5:329-337, 2003). In this report, we provide genetic and biochemical evidence that salB encodes a secreted protein that is expressed from a monocistronic stress-inducible operon. Consistent with CroR being a direct transcriptional activator of the salB expression, CroR was found to bind to the salB promoter region in electrophoretic mobility shift assays. Interestingly, we provide evidence that SalB does not play a role in the intrinsic β-lactam resistance associated with CroRS. We also show that the CroRS system is able to regulate its own expression. The sequence of the CroRS binding site in the salB and croR promoter regions was determined using DNase I footprinting assays.

scholarly journals Transition State Regulator AbrB Inhibits Transcription of Bacillus amyloliquefaciens FZB45 Phytase through Binding at Two Distinct Sites Located within the Extended phyC Promoter Region

2008 ◽  
Vol 190 (19) ◽  
pp. 6467-6474 ◽  
Author(s):  
Oliwia Makarewicz ◽  
Svetlana Neubauer ◽  
Corinna Preusse ◽  
Rainer Borriss
Keyword(s):  
Bacillus Amyloliquefaciens ◽  
Promoter Region ◽  
Response Regulator ◽  
Dependent Manner ◽  
Coding Region ◽  
Mobility Shift ◽  
Dnase I Footprinting ◽  
Regulator Protein ◽  
Transition State Regulator ◽  
Gel Mobility Shift

ABSTRACT We have previously identified the phyC gene of Bacillus amyloliquefaciens FZB45, encoding extracellular phytase, as a member of the PhoP regulon, which is expressed only during phosphate starvation. Its σA-dependent promoter is positively and negatively regulated by the phosphorylated PhoP response regulator in a phosphate-dependent manner (O. Makarewicz, S. Dubrac, T. Msadek, and R. Borriss, J. Bacteriol. 188:6953-6965, 2006). Here, we provide experimental evidence that the transcription of phyC underlies a second control mechanism exerted by the global transient-phase regulator protein, AbrB, which hinders its expression during exponential growth. Gel mobility shift and DNase I footprinting experiments demonstrated that AbrB binds to two different regions in the phyC promoter region that are separated by about 200 bp. One binding site is near the divergently orientated yodU gene, and the second site is located downstream of the phyC promoter and extends into the coding region of the phyC gene. Cooperative binding to the two distant binding regions is necessary for the AbrB-directed repression of phyC transcription. AbrB does not affect the transcription of the neighboring yodU gene.

Phosphorylation activity of the response regulator of the two-component signal transduction system AtoS–AtoC in E. coli

2005 ◽  
Vol 1725 (3) ◽  
pp. 257-268 ◽  
Author(s):  
Efthimia E. Lioliou ◽  
Eleni P. Mimitou ◽  
Asterios I. Grigoroudis ◽  
Cynthia H. Panagiotidis ◽  
Christos A. Panagiotidis ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Response Regulator ◽  
Signal Transduction System ◽  
E Coli ◽  
Two Component ◽  
Two Component Signal Transduction

scholarly journals CheX in the Three-Phosphatase System of Bacterial Chemotaxis

2007 ◽  
Vol 189 (19) ◽  
pp. 7007-7013 ◽  
Author(s):  
Travis J. Muff ◽  
Richard M. Foster ◽  
Peter J. Y. Liu ◽  
George W. Ordal
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Bacillus Subtilis ◽  
Mutant Strain ◽  
Response Regulator ◽  
Bacterial Chemotaxis ◽  
Signal Transduction System ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Phosphatase System

ABSTRACT Bacterial chemotaxis involves the regulation of motility by a modified two-component signal transduction system. In Escherichia coli, CheZ is the phosphatase of the response regulator CheY but many other bacteria, including Bacillus subtilis, use members of the CheC-FliY-CheX family for this purpose. While Bacillus subtilis has only CheC and FliY, many systems also have CheX. The effect of this three-phosphatase system on chemotaxis has not been studied previously. CheX was shown to be a stronger CheY-P phosphatase than either CheC or FliY. In Bacillus subtilis, a cheC mutant strain was nearly complemented by heterologous cheX expression. CheX was shown to overcome the ΔcheC adaptational defect but also generally lowered the counterclockwise flagellar rotational bias. The effect on rotational bias suggests that CheX reduced the overall levels of CheY-P in the cell and did not truly replicate the adaptational effects of CheC. Thus, CheX is not functionally redundant to CheC and, as outlined in the discussion, may be more analogous to CheZ.

scholarly journals Systematic Inactivation and Phenotypic Characterization of Two-Component Signal Transduction Systems of Enterococcus faecalis V583

2004 ◽  
Vol 186 (23) ◽  
pp. 7951-7958 ◽  
Author(s):  
Lynn E. Hancock ◽  
Marta Perego
Keyword(s):  
Signal Transduction ◽  
Antibiotic Resistance ◽  
Environmental Stress ◽  
Enterococcus Faecalis ◽  
Response Regulator ◽  
Phenotypic Characterization ◽  
Response Regulators ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Biofilm Development

ABSTRACT The ability of enterococci to adapt and respond to different environmental stimuli, including the host environment, led us to investigate the role of two-component signal transduction in the regulation of Enterococcus faecalis physiology. Using a bioinformatic approach, we previously identified 17 two-component systems (TCS), consisting of a sensory histidine kinase and the cognate response regulator, as well as an additional orphan response regulator (L. E. Hancock and M. Perego, J. Bacteriol. 184:5819-5825, 2002). In an effort to identify the potential function of each TCS in the biology of E. faecalis clinical isolate strain V583, we constructed insertion mutations in each of the response regulators. We were able to inactivate 17 of 18 response regulators, the exception being an ortholog of YycF, previously shown to be essential for viability in a variety of gram-positive microorganisms. The biological effects of the remaining mutations were assessed by using a number of assays, including antibiotic resistance, biofilm formation, and environmental stress. We identified TCS related to antibiotic resistance and environmental stress and found one system which controls the initiation of biofilm development by E. faecalis.

scholarly journals Cpx Two-Component Signal Transduction inEscherichia coli: Excessive CpxR-P Levels Underlie CpxA* Phenotypes

2000 ◽  
Vol 182 (5) ◽  
pp. 1423-1426 ◽  
Author(s):  
Peter De Wulf ◽  
E. C. C. Lin
Keyword(s):  
Signal Transduction ◽  
Response Regulator ◽  
Response Regulators ◽  
Signal Transduction System ◽  
Regulate Gene Expression ◽  
Adverse Conditions ◽  
Two Component ◽  
Sensor Protein ◽  
Two Component Signal Transduction ◽  
Cognate Response Regulator

ABSTRACT In Escherichia coli, the CpxA-CpxR two-component signal transduction system and the ςE and ς32response pathways jointly regulate gene expression in adaptation to adverse conditions. These include envelope protein distress, heat shock, oxidative stress, high pH, and entry into stationary phase. Certain mutant versions of the CpxA sensor protein (CpxA* proteins) exhibit an elevated ratio of kinase to phosphatase activity on CpxR, the cognate response regulator. As a result, CpxA* strains display numerous phenotypes, many of which cannot be easily related to currently known functions of the CpxA-CpxR pathway. It is unclear whether CpxA* phenotypes are caused solely by hyperphosphorylation of CpxR. We here report that all of the tested CpxA* phenotypes depend on elevated levels of CpxR-P and not on cross-signalling of CpxA* to noncognate response regulators.

scholarly journals VraR Binding to the Promoter Region of agr Inhibits Its Function in Vancomycin-Intermediate Staphylococcus aureus (VISA) and Heterogeneous VISA

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Yuanyuan Dai ◽  
Wenjiao Chang ◽  
Changcheng Zhao ◽  
Jing Peng ◽  
Liangfei Xu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Promoter Region ◽  
Reference Strain ◽  
Vancomycin Resistance ◽  
Mobility Shift ◽  
Content Type ◽  
Promoter Sequences ◽  
Dnase I Footprinting ◽  
Resistant Strains ◽  
Electrophoretic Mobility Shift Assays

ABSTRACT Acquisition of vancomycin resistance in Staphylococcus aureus is often accompanied by a reduction in virulence, but the mechanisms underlying this change remain unclear. The present study was undertaken to investigate this process in a clinical heterogeneous vancomycin-intermediate S. aureus (hVISA) strain, 10827; an hVISA reference strain, Mu3; and a VISA reference strain, Mu50, along with their respective series of vancomycin-induced resistant strains. In these strains, increasing MICs of vancomycin were associated with increased expression of the vancomycin resistance-associated regulator gene (vraR) and decreased expression of virulence genes (hla, hlb, and coa) and virulence-regulated genes (RNAIII, agrA, and saeR). These results suggested that VraR might have a direct or indirect effect on virulence in S. aureus. In electrophoretic mobility shift assays, VraR did not bind to promoter sequences of hla, hlb, and coa genes, but it did bind to the agr promoter region. In DNase I footprinting assays, VraR protected a 15-nucleotide (nt) sequence in the intergenic region between the agr P2 and P3 promoters. These results indicated that when S. aureus is subject to induction by vancomycin, expression of vraR is upregulated, and VraR binding inhibits the function of the Agr quorum-sensing system, causing reductions in the virulence of VISA/hVISA strains. Our results suggested that VraR in S. aureus is involved not only in the regulation of vancomycin resistance but also in the regulation of virulence.

scholarly journals Development and Validation of a High-Throughput Cell-Based Screen To Identify Activators of a Bacterial Two-Component Signal Transduction System

2015 ◽  
Vol 59 (7) ◽  
pp. 3789-3799 ◽  
Author(s):  
Julia J. van Rensburg ◽  
Kate R. Fortney ◽  
Lan Chen ◽  
Andrew J. Krieger ◽  
Bruno P. Lima ◽  
...  
Keyword(s):  
Signal Transduction ◽  
High Throughput ◽  
Response Regulator ◽  
Phosphoryl Group ◽  
Signal Transduction System ◽  
Membrane Repair ◽  
Content Type ◽  
Two Component ◽  
Serovar Typhimurium ◽  
Two Component Signal Transduction

ABSTRACTCpxRA is a two-component signal transduction system (2CSTS) found in many drug-resistant Gram-negative bacteria. In response to periplasmic stress, CpxA autophosphorylates and donates a phosphoryl group to its cognate response regulator, CpxR. Phosphorylated CpxR (CpxR-P) upregulates genes involved in membrane repair and downregulates multiple genes that encode virulence factors, which are trafficked across the cell membrane. Mutants that constitutively activate CpxRA inSalmonella entericaserovar Typhimurium andHaemophilus ducreyiare avirulent in mice and humans, respectively. Thus, the activation of CpxRA has high potential as a novel antimicrobial/antivirulence strategy. Using a series ofEscherichia colistrains containing a CpxR-P-responsivelacZreporter and deletions in genes encoding CpxRA system components, we developed and validated a novel cell-based high-throughput screen (HTS) for CpxRA activators. A screen of 36,000 compounds yielded one hit compound that increased reporter activity in wild-type cells. This is the first report of a compound that activates, rather than inhibits, a 2CSTS. The activity profile of the compound against CpxRA pathway mutants in the presence of glucose suggested that the compound inhibits CpxA phosphatase activity. We confirmed that the compound induced the accumulation of CpxR-P in treated cells. Although the hit compound contained a nitro group, a derivative lacking this group retained activity in serum and had lower cytotoxicity than that of the initial hit. This HTS is amenable for the screening of larger libraries to find compounds that activate CpxRA by other mechanisms, and it could be adapted to find activators of other two-component systems.

scholarly journals Analysis of Protein Expression Regulated by the Helicobacter pylori ArsRS Two-Component Signal Transduction System

2010 ◽  
Vol 192 (8) ◽  
pp. 2034-2043 ◽  
Author(s):  
John T. Loh ◽  
Shobhana S. Gupta ◽  
David B. Friedman ◽  
Andrzej M. Krezel ◽  
Timothy L. Cover
Keyword(s):  
Signal Transduction ◽  
Helicobacter Pylori ◽  
Protein Expression ◽  
Thioredoxin Reductase ◽  
Acid Resistance ◽  
Wild Type ◽  
Signal Transduction System ◽  
Promoter Regions ◽  
Two Component ◽  
Two Component Signal Transduction

ABSTRACT Previous studies have shown that the Helicobacter pylori ArsRS two-component signal transduction system contributes to acid-responsive gene expression. To identify additional members of the ArsRS regulon and further investigate the regulatory role of the ArsRS system, we analyzed protein expression in wild-type and arsS null mutant strains. Numerous proteins were differentially expressed in an arsS mutant strain compared to a wild-type strain when the bacteria were cultured at pH 5.0 and also when they were cultured at pH 7.0. Genes encoding 14 of these proteins were directly regulated by the ArsRS system, based on observed binding of ArsR to the relevant promoter regions. The ArsRS-regulated proteins identified in this study contribute to acid resistance (urease and amidase), acetone metabolism (acetone carboxylase), resistance to oxidative stress (thioredoxin reductase), quorum sensing (Pfs), and several other functions. These results provide further definition of the ArsRS regulon and underscore the importance of the ArsRS system in regulating expression of H. pylori proteins during bacterial growth at both neutral pH and acidic pH.

scholarly journals A Two-Component Signal Transduction System Essential for Growth of Bacillus subtilis: Implications for Anti-Infective Therapy

1998 ◽  
Vol 180 (23) ◽  
pp. 6375-6383 ◽  
Author(s):  
Céline Fabret ◽  
James A. Hoch
Keyword(s):  
Signal Transduction ◽  
Response Regulator ◽  
Temperature Sensitive ◽  
Protease Gene ◽  
Signal Transduction System ◽  
Insertional Inactivation ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
High Level ◽  
Promoter Studies

ABSTRACT A two-component signal transduction system encoded by theyycF and yycG genes is part of an operon containing three genes, yycH, yycI, andyycJ, with no known function and a gene, yycK, coding for an HtrA-like protease. This operon was transcribed during growth, and its transcription shut down as the cells approached stationary phase. This decreased transcription was not Spo0A dependent. The HtrA protease gene was separately controlled during sporulation from a ςG promoter. Studies using insertional inactivation plasmids revealed that neither yycF noryycG could be inactivated, whereas the other genes were inactivated without loss of viability. A temperature-sensitive YycF response regulator mutant was isolated and shown to have an H215P mutation in a putative DNA-binding domain which is closely related to the OmpR family of response regulators. At the nonpermissive temperature, cultures of the mutant strain stopped growth within 30 min, and this was followed by a decrease in optical density. Microscopically, many of the cells appeared to retain their structure while being empty of their contents. The essential processes regulated by this two-component system remain unknown. A search of the genome databases revealed YycF, YycG, and YycJ homologues encoded by three linked genes in Streptococcus pyogenes. The high level of identity of these proteins (71% for YycF) suggests that this system may play a similar role in gram-positive pathogens.

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