scholarly journals DdrI, a cAMP Receptor Protein Family Member, Acts as a Major Regulator for Adaptation ofDeinococcus radioduransto Various Stresses

2018 ◽  
Vol 200 (13) ◽  
Author(s):  
Laura Meyer ◽  
Geneviève Coste ◽  
Suzanne Sommer ◽  
Jacques Oberto ◽  
Fabrice Confalonieri ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Division ◽  
Heat Shock ◽  
Receptor Protein ◽  
Dependent Manner ◽  
Central Metabolism ◽  
Camp Receptor Protein ◽  
Content Type ◽  
Dna Damaging Agents ◽  
Camp Receptor

ABSTRACTTheDNAdamageresponseddrIgene encodes a transcription regulator belonging to the cAMP receptor protein (CRP) family. Cells devoid of the DdrI protein exhibit a pleiotropic phenotype, including growth defects and sensitivity to DNA-damaging agents and to oxidative stress. Here, we show that the absence of the DdrI protein also confers sensitivity to heat shock treatment, and several genes involved in heat shock response were shown to be upregulated in a DdrI-dependent manner. Interestingly, expression of theEscherichia coliCRP partially compensates for the absence of the DdrI protein. Microscopic observations of ΔddrImutant cells revealed an increased proportion of two-tetrad and anucleated cells in the population compared to the wild-type strain, indicating that DdrI is crucial for the completion of cell division and/or chromosome segregation. We show that DdrI is also involved in the megaplasmid MP1 stability and in efficient plasmid transformation by facilitating the maintenance of the incoming plasmid in the cell. Thein silicoprediction of putative DdrI binding sites in theD. radioduransgenome suggests that hundreds of genes, belonging to several functional groups, may be regulated by DdrI. In addition, the DdrI protein absolutely requires cAMP forin vitrobinding to specific target sequences, and it acts as a dimer. All these data underline the major role of DdrI inD. radioduransphysiology under normal and stress conditions by regulating, both directly and indirectly, a cohort of genes involved in various cellular processes, including central metabolism and specific responses to diverse harmful environments.IMPORTANCEDeinococcus radioduranshas been extensively studied to elucidate the molecular mechanisms responsible for its exceptional ability to withstand lethal effects of various DNA-damaging agents. A complex network, including efficient DNA repair, protein protection against oxidation, and diverse metabolic pathways, plays a crucial role for its radioresistance. The regulatory networks orchestrating these various pathways are still missing. Our data provide new insights into the crucial contribution of the transcription factor DdrI for theD. radioduransability to withstand harmful conditions, including UV radiation, mitomycin C treatment, heat shock, and oxidative stress. Finally, we highlight that DdrI is also required for accurate cell division, for maintenance of plasmid replicons, and for central metabolism processes responsible for the overall cell physiology.

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 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 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 Expression of the cpdA Gene, Encoding a 3′,5′-Cyclic AMP (cAMP) Phosphodiesterase, Is Positively Regulated by the cAMP-cAMP Receptor Protein Complex

2008 ◽  
Vol 191 (3) ◽  
pp. 922-930 ◽  
Author(s):  
Han-Suk Kim ◽  
Sung-Min Kim ◽  
Hyun-Jung Lee ◽  
Soon-Jung Park ◽  
Kyu-Ho Lee
Keyword(s):  
Regulatory Region ◽  
Site Directed Mutagenesis ◽  
Receptor Protein ◽  
Upstream Region ◽  
Intracellular Camp ◽  
Dependent Manner ◽  
Multicopy Plasmid ◽  
Camp Receptor Protein ◽  
Camp Phosphodiesterase ◽  
Camp Receptor

ABSTRACT The intracellular level of cyclic 3′,5′-AMP (cAMP), a signaling molecule that mediates a variety of cellular processes, is finely modulated by the regulation of its synthesis, excretion, and degradation. In this study, cAMP phosphodiesterase (CpdA), an enzyme that catalyzes the conversion of cAMP to AMP, was characterized in a pathogenic bacterium, Vibrio vulnificus. The cpdA gene exists in an operon composed of mutT, yqiB, cpdA, and yqiA, the transcription of which was initiated at position −22 upstream of mutT. A cpdA-null mutant of V. vulnificus contained significantly higher levels of cAMP than the wild type but showed no detectable cAMP when a multicopy plasmid of the cpdA gene was provided in trans, suggesting that CpdA is responsible for cAMP degradation. Cellular contents of the CpdA protein decreased dramatically in both cya and crp mutants. In addition, levels of expression of the cpdA::luxAB transcription fusion decreased in cya and crp mutants. The level of expression of cpdA::luxAB in the cya mutant increased in a concentration-dependent manner upon the exogenous addition of cAMP. The cAMP-cAMP receptor protein (CRP) complex bound directly to the upstream region of mutT, which includes a putative CRP-binding sequence centered at position −95.5 relative to the transcription start site. Site-directed mutagenesis or the deletion of this sequence in the cpdA::luxAB transcription fusion resulted in the loss of regulation by cAMP and CRP. Thus, this study demonstrates that CpdA plays a crucial role in determining the intracellular cAMP level and shows for the first time that the expression of cpdA is activated by the cAMP-CRP complex via direct binding to the regulatory region.

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.

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