scholarly journals Cra and cAMP Receptor Protein Have Opposing Roles in the Regulation of fruB in Vibrio cholerae

2021 ◽  
Vol 203 (10) ◽  
Author(s):  
Christina Beck ◽  
Sayde Perry ◽  
Daniel M. Stoebel ◽  
Jane M. Liu
Keyword(s):  
Vibrio Cholerae ◽  
Molecular Mechanisms ◽  
Carbon Sources ◽  
Receptor Protein ◽  
Camp Receptor Protein ◽  
Phosphotransferase System ◽  
Content Type ◽  
Catabolite Repressor ◽  
Available Carbon ◽  
Camp Receptor

ABSTRACT The Gram-negative bacterium Vibrio cholerae adapts to changes in the environment by selectively producing the necessary machinery to take up and metabolize available carbohydrates. The import of fructose by the fructose-specific phosphoenolpyruvate (PEP) phosphotransferase system (PTS) is of particular interest because of its putative connection to cholera pathogenesis and persistence. Here, we describe the expression and regulation of fruB, which encodes an EIIA-FPr fusion protein as part of the fructose-specific PTS in V. cholerae. Using a series of transcriptional reporter fusions and additional biochemical and genetic assays, we identified Cra (catabolite repressor/activator) and cAMP receptor protein (CRP) as regulators of fruB expression and determined that this regulation is dependent upon the presence or absence of PTS sugars. Cra functions as a repressor, downregulating fruB expression in the absence of fructose when components of PTSFru are not needed. CRP functions as an activator of fruB expression. We also report that Cra and CRP can affect fruB expression independently; however, CRP can modulate cra expression in the presence of fructose and glucose. Evidence from this work provides the foundation for continued investigations into PTSFru and its relationship to the V. cholerae life cycle. IMPORTANCE Vibrio cholerae is the causative agent of cholera disease. While current treatments of care are accessible, we still lack an understanding of the molecular mechanisms that allow V. cholerae to survive in both aquatic reservoirs and the human small intestine, where pathogenesis occurs. Central to V. cholerae’s survival is its ability to use available carbon sources. Here, we investigate the regulation of fruB, which encodes a protein central to the import and metabolism of fructose. We show that fruB expression is controlled by the transcriptional regulators Cra and CRP. This work contributes toward a clearer understanding of how carbon source availability impacts the physiology and, potentially, the persistence of the pathogen.

scholarly journals Positive Effect of Carbon Sources on Natural Transformation in Escherichia coli: Role of Low-Level Cyclic AMP (cAMP)-cAMP Receptor Protein in the Derepression ofrpoS

2015 ◽  
Vol 197 (20) ◽  
pp. 3317-3328 ◽  
Author(s):  
Mengyue Guo ◽  
Huanyu Wang ◽  
Nengbin Xie ◽  
Zhixiong Xie
Keyword(s):  
Escherichia Coli ◽  
Natural Transformation ◽  
Carbon Sources ◽  
Transformation Frequency ◽  
Receptor Protein ◽  
Camp Receptor Protein ◽  
Content Type ◽  
E Coli ◽  
Camp Receptor

ABSTRACTNatural plasmid transformation ofEscherichia coliis a complex process that occurs strictly on agar plates and requires the global stress response factor σS. Here, we showed that additional carbon sources could significantly enhance the transformability ofE. coli. Inactivation of phosphotransferase system genes (ptsH,ptsG, andcrr) caused an increase in the transformation frequency, and the addition of cyclic AMP (cAMP) neutralized the promotional effect of carbon sources. This implies a negative role of cAMP in natural transformation. Further study showed thatcrpandcyaAmutations conferred a higher transformation frequency, suggesting that the cAMP-cAMP receptor protein (CRP) complex has an inhibitory effect on transformation. Moreover, we observed thatrpoSis negatively regulated by cAMP-CRP in early log phase and that bothcrpandcyaAmutants show no transformation superiority whenrpoSis knocked out. Therefore, it can be concluded that both thecrpandcyaAmutations derepressrpoSexpression in early log phase, whereby they aid in the promotion of natural transformation ability. We also showed that the accumulation of RpoS during early log phase can account for the enhanced transformation aroused by additional carbon sources. Our results thus demonstrated that the presence of additional carbon sources promotes competence development and natural transformation by reducing cAMP-CRP and, thus, derepressingrpoSexpression during log phase. This finding could contribute to a better understanding of the relationship between nutrition state and competence, as well as the mechanism of natural plasmid transformation inE. coli.IMPORTANCEEscherichia coli, which is not usually considered to be naturally transformable, was found to spontaneously take up plasmid DNA on agar plates. Researching the mechanism of natural transformation is important for understanding the role of transformation in evolution, as well as in the transfer of pathogenicity and antibiotic resistance genes. In this work, we found that carbon sources significantly improve transformation by decreasing cAMP. Then, the low level of cAMP-CRP derepresses the general stress response regulator RpoS via a biphasic regulatory pattern, thereby contributing to transformation. Thus, we demonstrate the mechanism by which carbon sources affect natural transformation, which is important for revealing information about the interplay between nutrition state and competence development inE. coli.

scholarly journals cAMP Receptor Protein ControlsVibrio choleraeGene Expression in Response to Host Colonization

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Jainaba Manneh-Roussel ◽  
James R. J. Haycocks ◽  
Andrés Magán ◽  
Nicolas Perez-Soto ◽  
Kerstin Voelz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Vibrio Cholerae ◽  
Expression Patterns ◽  
Lifestyle Changes ◽  
Receptor Protein ◽  
Camp Receptor Protein ◽  
Host Colonization ◽  
Content Type ◽  
Camp Receptor

ABSTRACTThe bacteriumVibrio choleraeis native to aquatic environments and can switch lifestyles to cause disease in humans. Lifestyle switching requires modulation of genetic systems for quorum sensing, intestinal colonization, and toxin production. Much of this regulation occurs at the level of gene expression and is controlled by transcription factors. In this work, we have mapped the binding of cAMP receptor protein (CRP) and RNA polymerase across theV. choleraegenome. We show that CRP is an integral component of the regulatory network that controls lifestyle switching. Focusing on a locus necessary for toxin transport, we demonstrate CRP-dependent regulation of gene expression in response to host colonization. Examination of further CRP-targeted genes reveals that this behavior is commonplace. Hence, CRP is a key regulator of manyV. choleraegenes in response to lifestyle changes.IMPORTANCECholera is an infectious disease that is caused by the bacteriumVibrio cholerae. Best known for causing disease in humans, the bacterium is most commonly found in aquatic ecosystems. Hence, humans acquire cholera following ingestion of food or water contaminated withV. cholerae. Transition between an aquatic environment and a human host triggers a lifestyle switch that involves reprogramming ofV. choleraegene expression patterns. This process is controlled by a network of transcription factors. In this paper, we show that the cAMP receptor protein (CRP) is a key regulator ofV. choleraegene expression in response to lifestyle changes.

scholarly journals A Putative Acetylation System in Vibrio cholerae Modulates Virulence in Arthropod Hosts

2018 ◽  
Vol 84 (21) ◽  
Author(s):  
Kalle Liimatta ◽  
Emily Flaherty ◽  
Gabby Ro ◽  
Duy K. Nguyen ◽  
Cecilia Prado ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Vibrio Cholerae ◽  
Molecular Mechanisms ◽  
Severe Disease ◽  
Receptor Protein ◽  
Protein Activity ◽  
Content Type ◽  
Camp Receptor ◽  
K 12

ABSTRACT Acetylation is a broadly conserved mechanism of covalently modifying the proteome to precisely control protein activity. In bacteria, central metabolic enzymes and regulatory proteins, including those involved in virulence, can be targeted for acetylation. In this study, we directly link a putative acetylation system to metabolite-dependent virulence in the pathogen Vibrio cholerae. We demonstrate that the cobB and yfiQ genes, which encode homologs of a deacetylase and an acetyltransferase, respectively, modulate V. cholerae metabolism of acetate, a bacterially derived short-chain fatty acid with important physiological roles in a diversity of host organisms. In Drosophila melanogaster, a model arthropod host for V. cholerae infection, the pathogen consumes acetate within the gastrointestinal tract, which contributes to fly mortality. We show that deletion of cobB impairs growth on acetate minimal medium, delays the consumption of acetate from rich medium, and reduces virulence of V. cholerae toward Drosophila. These impacts can be reversed by complementing cobB or by introducing a deletion of yfiQ into the ΔcobB background. We further show that cobB controls the accumulation of triglycerides in the Drosophila midgut, which suggests that cobB directly modulates metabolite levels in vivo. In Escherichia coli K-12, yfiQ is upregulated by cAMP-cAMP receptor protein (CRP), and we identified a similar pattern of regulation in V. cholerae, arguing that the system is activated in response to similar environmental cues. In summary, we demonstrate that proteins likely involved in acetylation can modulate the outcome of infection by regulating metabolite exchange between pathogens and their colonized hosts. IMPORTANCE The bacterium Vibrio cholerae causes severe disease in humans, and strains can persist in the environment in association with a wide diversity of host species. By investigating the molecular mechanisms that underlie these interactions, we can better understand constraints affecting the ecology and evolution of this global pathogen. The Drosophila model of Vibrio cholerae infection has revealed that bacterial regulation of acetate and other small metabolites from within the fly gastrointestinal tract is crucial for its virulence. Here, we demonstrate that genes that may modify the proteome of V. cholerae affect virulence toward Drosophila, most likely by modulating central metabolic pathways that control the consumption of acetate as well as other small molecules. These findings further highlight the many layers of regulation that tune bacterial metabolism to alter the trajectory of interactions between bacteria and their hosts.

scholarly journals Cyclic AMP (cAMP) Receptor Protein-cAMP Complex Regulates Heparosan Production in Escherichia coli Strain Nissle 1917

2015 ◽  
Vol 81 (22) ◽  
pp. 7687-7696 ◽  
Author(s):  
Huihui Yan ◽  
Feifei Bao ◽  
Liping Zhao ◽  
Yanying Yu ◽  
Jiaqin Tang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cyclic Amp ◽  
Carbon Sources ◽  
Coli Strain ◽  
Site Directed Mutagenesis ◽  
Receptor Protein ◽  
Upstream Region ◽  
Camp Receptor Protein ◽  
Content Type ◽  
Camp Receptor

ABSTRACTHeparosan serves as the starting carbon backbone for the chemoenzymatic synthesis of heparin, a widely used clinical anticoagulant drug. The availability of heparosan is a significant concern for the cost-effective synthesis of bioengineered heparin. The carbon source is known as the pivotal factor affecting heparosan production. However, the mechanism by which carbon sources control the biosynthesis of heparosan is unclear. In this study, we found that the biosynthesis of heparosan was influenced by different carbon sources. Glucose inhibits the biosynthesis of heparosan, while the addition of either fructose or mannose increases the yield of heparosan. Further study demonstrated that the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex binds to the upstream region of the region 3 promoter and stimulates the transcription of the gene cluster for heparosan biosynthesis. Site-directed mutagenesis of the CRP binding site abolished its capability of binding CRP and eliminated the stimulative effect on transcription.1H nuclear magnetic resonance (NMR) analysis was further performed to determine theEscherichia colistrain Nissle 1917 (EcN) heparosan structure and quantify extracellular heparosan production. Our results add to the understanding of the regulation of heparosan biosynthesis and may contribute to the study of other exopolysaccharide-producing strains.

scholarly journals Repression of VvpM Protease Expression by Quorum Sensing and the cAMP-cAMP Receptor Protein Complex inVibrio vulnificus

2018 ◽  
Vol 200 (7) ◽  
Author(s):  
Jeong-A Kim ◽  
Mi-Ae Lee ◽  
You-Chul Jung ◽  
Bo-Ram Jang ◽  
Kyu-Ho Lee
Keyword(s):  
Transcription Factors ◽  
Stationary Phase ◽  
Cell Density ◽  
Transcription Initiation ◽  
Vibrio Vulnificus ◽  
The Other ◽  
Receptor Protein ◽  
Camp Receptor Protein ◽  
Content Type ◽  
Camp Receptor

ABSTRACTSepticemia-causingVibrio vulnificusproduces at least three exoproteases, VvpE, VvpS, and VvpM, all of which participate in interactions with human cells. Expression of VvpE and VvpS is induced in the stationary phase by multiple transcription factors, including sigma factor S, SmcR, and the cAMP-cAMP receptor protein (cAMP-CRP) complex. Distinct roles of VvpM, such as induction of apoptosis, lead us to hypothesize VvpM expression is different from that of the other exoproteases. Its transcription, which was found to be independent of sigma S, is induced at the early exponential phase and then becomes negligible upon entry into the stationary phase. SmcR and CRP were studied regarding the control ofvvpMexpression. Transcription ofvvpMwas repressed by SmcR and cAMP-CRP complex individually, which specifically bound to the regions −2 to +20 and +6 to +27, respectively, relative to thevvpMtranscription initiation site. Derepression ofvvpMgene expression was 10- to 40-fold greater in ansmcR crpdouble mutant than in single-gene mutants. Therefore, these results show that the expression ofV. vulnificusexoproteases is differentially regulated, and in this way, distinct proteases can engage in specific interactions with a host.IMPORTANCEAn opportunistic human pathogen,Vibrio vulnificusproduces multiple extracellular proteases that are involved in diverse interactions with a host. The total exoproteolytic activity is detected mainly in the supernatants of the high-cell-density cultures. However, some proteolytic activity derived from a metalloprotease, VvpM, was present in the supernatants of the low-cell-density cultures sampled at the early growth period. In this study, we present the regulatory mechanism for VvpM expression via repression by at least two transcription factors. This type of transcriptional regulation is the exact opposite of those for expression of the otherV. vulnificusexoproteases. Differential regulation of each exoprotease's production then facilitates the pathogen's participation in the distinct interactions with a host.

scholarly journals Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137529 ◽  
Author(s):  
M. Shamim Hasan Zahid ◽  
Sharda Prasad Awasthi ◽  
Masahiro Asakura ◽  
Shruti Chatterjee ◽  
Atsushi Hinenoya ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Vibrio Cholerae ◽  
Receptor Protein ◽  
Protein Signaling ◽  
Camp Receptor Protein ◽  
Signaling System ◽  
Camp Receptor

scholarly journals cAMP Receptor Protein Positively Regulates the Expression of Genes Involved in the Biosynthesis of Klebsiella oxytoca Tilivalline Cytotoxin

2021 ◽  
Vol 12 ◽  
Author(s):  
Diana Rodríguez-Valverde ◽  
Nancy León-Montes ◽  
Jorge Soria-Bustos ◽  
Jessica Martínez-Cruz ◽  
Ricardo González-Ugalde ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Regulation ◽  
Divalent Cations ◽  
Klebsiella Oxytoca ◽  
Carbon Sources ◽  
Enteric Bacteria ◽  
Receptor Protein ◽  
Camp Receptor Protein ◽  
Environmental Signals ◽  
Camp Receptor

Klebsiella oxytoca is a resident of the human gut. However, certain K. oxytoca toxigenic strains exist that secrete the nonribosomal peptide tilivalline (TV) cytotoxin. TV is a pyrrolobenzodiazepine that causes antibiotic-associated hemorrhagic colitis (AAHC). The biosynthesis of TV is driven by enzymes encoded by the aroX and NRPS operons. In this study, we determined the effect of environmental signals such as carbon sources, osmolarity, and divalent cations on the transcription of both TV biosynthetic operons. Gene expression was enhanced when bacteria were cultivated in tryptone lactose broth. Glucose, high osmolarity, and depletion of calcium and magnesium diminished gene expression, whereas glycerol increased transcription of both TV biosynthetic operons. The cAMP receptor protein (CRP) is a major transcriptional regulator in bacteria that plays a key role in metabolic regulation. To investigate the role of CRP on the cytotoxicity of K. oxytoca, we compared levels of expression of TV biosynthetic operons and synthesis of TV in wild-type strain MIT 09-7231 and a Δcrp isogenic mutant. In summary, we found that CRP directly activates the transcription of the aroX and NRPS operons and that the absence of CRP reduced cytotoxicity of K. oxytoca on HeLa cells, due to a significant reduction in TV production. This study highlights the importance of the CRP protein in the regulation of virulence genes in enteric bacteria and broadens our knowledge on the regulatory mechanisms of the TV cytotoxin.

scholarly journals Sycrp2 Is Essential for Twitching Motility in the CyanobacteriumSynechocystissp. Strain PCC 6803

2018 ◽  
Vol 200 (21) ◽  
Author(s):  
Wei-Yu Song ◽  
Sha-Sha Zang ◽  
Zheng-Ke Li ◽  
Guo-Zheng Dai ◽  
Ke Liu ◽  
...  
Keyword(s):  
Cell Motility ◽  
Receptor Protein ◽  
Upstream Region ◽  
Twitching Motility ◽  
Camp Receptor Protein ◽  
Mobility Shift ◽  
Content Type ◽  
Receptor Proteins ◽  
Camp Receptor ◽  
Pcc 6803

ABSTRACTTwo cAMP receptor proteins (CRPs), Sycrp1 (encoded bysll1371) and Sycrp2 (encoded bysll1924), exist in the cyanobacteriumSynechocystissp. strain PCC 6803. Previous studies have demonstrated that Sycrp1 has binding affinity for cAMP and is involved in motility by regulating the formation of pili. However, the function of Sycrp2 remains unknown. Here, we report thatsycrp2disruption results in the loss of motility ofSynechocystissp. PCC 6803, and that the phenotype can be recovered by reintroducing thesycrp2gene into the genome ofsycrp2-disrupted mutants. Electron microscopy showed that thesycrp2-disrupted mutant lost the pilus apparatus on the cell surface, resulting in a lack of cell motility. Furthermore, the transcript level of thepilA9-pilA11operon (essential for cell motility and regulated by the cAMP receptor protein Sycrp1) was markedly decreased insycrp2-disrupted mutants compared with the wild-type strain. Moreover, yeast two-hybrid analysis and a pulldown assay demonstrated that Sycrp2 interacted with Sycrp1 to form a heterodimer and that Sycrp1 and Sycrp2 interacted with themselves to form homodimers. Gel mobility shift assays revealed that Sycrp1 specifically binds to the upstream region ofpilA9. Together, these findings indicate that inSynechocystissp. PCC 6803, Sycrp2 regulates the formation of pili and cell motility by interacting with Sycrp1.IMPORTANCEcAMP receptor proteins (CRPs) are widely distributed in cyanobacteria and play important roles in regulating gene expression. Although many cyanobacterial species have two cAMP receptor-like proteins, the functional links between them are unknown. Here, we found that Sycrp2 in the cyanobacteriumSynechocystissp. strain PCC 6803 is essential for twitching motility and that it interacts with Sycrp1, a known cAMP receptor protein involved with twitching motility. Our findings indicate that the two cAMP receptor-like proteins in cyanobacteria do not have functional redundancy but rather work together.

scholarly journals Interplay between Cyclic AMP-Cyclic AMP Receptor Protein and Cyclic di-GMP Signaling in Vibrio cholerae Biofilm Formation

2008 ◽  
Vol 190 (20) ◽  
pp. 6646-6659 ◽  
Author(s):  
Jiunn C. N. Fong ◽  
Fitnat H. Yildiz
Keyword(s):  
Cyclic Amp ◽  
Vibrio Cholerae ◽  
Transcriptome Analysis ◽  
Biofilm Formation ◽  
Matrix Proteins ◽  
Receptor Protein ◽  
Camp Receptor Protein ◽  
Genes Encoding ◽  
Camp Receptor ◽  
Biofilm Matrix

ABSTRACT Vibrio cholerae is a facultative human pathogen. The ability of V. cholerae to form biofilms is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. Formation of mature biofilms requires the production of extracellular matrix components, including Vibrio polysaccharide (VPS) and matrix proteins. Biofilm formation is positively controlled by the transcriptional regulators VpsR and VpsT and is negatively regulated by the quorum-sensing transcriptional regulator HapR, as well as the cyclic AMP (cAMP)-cAMP receptor protein (CRP) regulatory complex. Transcriptome analysis of cyaA (encoding adenylate cyclase) and crp (encoding cAMP receptor protein) deletion mutants revealed that cAMP-CRP negatively regulates transcription of both VPS biosynthesis genes and genes encoding biofilm matrix proteins. Further mutational and expression analysis revealed that cAMP-CRP negatively regulates transcription of vps genes indirectly through its action on vpsR transcription. However, negative regulation of the genes encoding biofilm matrix proteins by cAMP-CRP can also occur independent of VpsR. Transcriptome analysis also revealed that cAMP-CRP regulates the expression of a set of genes encoding diguanylate cyclases (DGCs) and phosphodiesterases. Mutational and phenotypic analysis of the differentially regulated DGCs revealed that a DGC, CdgA, is responsible for the increase in biofilm formation in the Δcrp mutant, showing the connection between of cyclic di-GMP and cAMP signaling in V. cholerae.

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