scholarly journals Regulation of streptokinase expression by CovR/S in Streptococcus pyogenes: CovR acts through a single high-affinity binding site

Microbiology ◽  
2009 ◽  
Vol 155 (2) ◽  
pp. 566-575 ◽  
Author(s):  
Gordon Churchward ◽  
Christopher Bates ◽  
Asiya A. Gusa ◽  
Virginia Stringer ◽  
June R. Scott
Keyword(s):  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Virulence Gene ◽  
Regulation Of Transcription ◽  
Virulence Gene Expression ◽  
Consensus Sequences ◽  
Dna Binding Sites ◽  
High Affinity Binding Site ◽  
Two Component Signal Transduction ◽  
Modes Of Interaction

The important human pathogen Streptococcus pyogenes (the group A streptococcus or GAS) produces many virulence factors that are regulated by the two-component signal transduction system CovRS (CsrRS). Dissemination of GAS infection originating at the skin has been shown to require production of streptokinase, whose transcription is repressed by CovR. In this work we have studied the interaction of CovR and phosphorylated CovR (CovR-P) with the promoter for streptokinase, Pska. We found that, in contrast to the other CovR-repressed promoters, Pska regulation by CovR occurs through binding at a single ATTARA consensus binding sequence (CB) that overlaps the −10 region of the promoter. Binding of CovR to other nearby consensus sequences occurs upon phosphorylation of the protein, but these other CBs do not contribute to the regulation of Pska by CovR. Thus, binding at a specific site does not necessarily indicate that the site is involved in regulation by CovR. In addition, at Pska, CovR binding to the different sites does not appear to involve cooperative interactions, which simplifies the analysis of CovR binding and gives us insight into the modes of interaction that occur between CovR and its specific DNA-binding sites. Finally, the observation that regulation of transcription from Pska occurs at a very low concentration of phosphorylated CovR may have important implications for the regulation of virulence gene expression during GAS infection.

scholarly journals Molecular Characteristics of Streptococcus pyogenes Isolated From Chinese Children With Different Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Dingle Yu ◽  
Yunmei Liang ◽  
Qinghua Lu ◽  
Qing Meng ◽  
Wenjian Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Streptococcus Pyogenes ◽  
Wide Spectrum ◽  
Expression Patterns ◽  
Virulence Gene ◽  
High Rate ◽  
Molecular Characteristics ◽  
Virulence Gene Expression ◽  
Obstructive Sleep

Streptococcus pyogenes is a bacterial pathogen that causes a wide spectrum of clinical diseases exclusively in humans. The distribution of emm type, antibiotic resistance and virulence gene expression for S. pyogenes varies temporally and geographically, resulting in distinct disease spectra. In this study, we analyzed antibiotic resistance and resistance gene expression patterns among S. pyogenes isolates from pediatric patients in China and investigated the relationship between virulence gene expression, emm type, and disease categories. Forty-two representative emm1.0 and emm12.0 strains (n = 20 and n = 22, respectively) isolated from patients with scarlet fever or obstructive sleep apnea-hypopnea syndrome were subjected to whole-genome sequencing and phylogenetic analysis. These strains were further analyzed for susceptibility to vancomycin. We found a high rate and degree of resistance to macrolides and tetracycline in these strains, which mainly expressed ermB and tetM. The disease category correlated with emm type but not superantigens. The distribution of vanuG and virulence genes were associated with emm type. Previously reported important prophages, such as φHKU16.vir, φHKU488.vir, Φ5005.1, Φ5005.2, and Φ5005.3 encoding streptococcal toxin, and integrative conjugative elements (ICEs) such as ICE-emm12 and ICE-HKU397 encoding macrolide and tetracycline resistance were found present amongst emm1 or emm12 clones from Shenzhen, China.

scholarly journals The RofA Binding Site in Streptococcus pyogenes Is Utilized in Multiple Transcriptional Pathways

2000 ◽  
Vol 182 (6) ◽  
pp. 1529-1540 ◽  
Author(s):  
Alexander B. Granok ◽  
Derek Parsonage ◽  
R. Paul Ross ◽  
Michael G. Caparon
Keyword(s):  
Binding Site ◽  
Streptococcus Pyogenes ◽  
Virulence Gene ◽  
Local Environment ◽  
Recognition Sequence ◽  
Direct Role ◽  
Virulence Gene Expression ◽  
Protein F ◽  
Adhesin Protein ◽  
Target Promoters

ABSTRACT Understanding the regulation of adhesins defines a pathogenic bacterium's interaction with the local environment within the host. In certain strains of Streptococcus pyogenes, transcription ofprtF, the gene which encodes the fibronectin-binding adhesin protein F, is activated by RofA under anaerobic conditions. RofA binds specifically to DNA in its target promoters and autoregulates its own expression. In this study, we have used DNase I protection assays to further investigate the interaction of RofA with its target promoters. In the region between rofA and the gene which encodes protein F (prtF), RofA binds to two distinct sites: a smaller site (17 bp) adjacent to the rofApromoter, and a larger site (40 bp) adjacent to the prtFpromoter. Analysis of fusions to a novel reporter gene whose product consists of the fusion of the N-terminal secretion domain of protein F with the C-terminal enzymatic domain of the enterococcal alkaline phosphatase (PhoZ) revealed that the small RofA binding site had no direct role in control of prtF transcription but contributed to regulation of rofA. Comparison in several strains representing different patterns of prtF expression indicated that the larger site was required for activation ofrofA and of prtF in all strains by both RofA-dependent and -independent pathways. Thus, it would appear that a common recognition sequence provides separate entries to a final common pathway in S. pyogenes virulence gene expression. The identification of multiple RofA-like proteins and promoters with RofA binding sites implies the existence of a widespread interacting regulatory network.

scholarly journals Use of a Phosphorylation Site Mutant To Identify Distinct Modes of Gene Repression by the Control of Virulence Regulator (CovR) in Streptococcus pyogenes

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Nicola Horstmann ◽  
Pranoti Sahasrabhojane ◽  
Hui Yao ◽  
Xiaoping Su ◽  
Samuel A. Shelburne
Keyword(s):  
Gene Expression ◽  
Streptococcus Pyogenes ◽  
Response Regulator ◽  
Phosphorylation Site ◽  
Virulence Gene ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Superficial Skin ◽  
Virulence Regulator ◽  
The Impact

ABSTRACT Control of the virulence regulator/sensor kinase (CovRS) two-component system (TCS) serves as a model for investigating the impact of signaling pathways on the pathogenesis of Gram-positive bacteria. However, the molecular mechanisms by which CovR, an OmpR/PhoB family response regulator, controls virulence gene expression are poorly defined, partly due to the labile nature of its aspartate phosphorylation site. To better understand the regulatory effect of phosphorylated CovR, we generated the phosphorylation site mutant strain 10870-CovR-D53E, which we predicted to have a constitutive CovR phosphorylation phenotype. Interestingly, this strain showed CovR activity only for a subset of the CovR regulon, which allowed for classification of CovR-influenced genes into D53E-regulated and D53E-nonregulated groups. Inspection of the promoter sequences of genes belonging to each group revealed distinct promoter architectures with respect to the location and number of putative CovR-binding sites. Electrophoretic mobility shift analysis demonstrated that recombinant CovR-D53E protein retains its ability to bind promoter DNA from both CovR-D53E-regulated and -nonregulated groups, implying that factors other than mere DNA binding are crucial for gene regulation. In fact, we found that CovR-D53E is incapable of dimerization, a process thought to be critical to OmpR/PhoB family regulator function. Thus, our global analysis of CovR-D53E indicates dimerization-dependent and dimerization-independent modes of CovR-mediated repression, thereby establishing distinct mechanisms by which this critical regulator coordinates virulence gene expression. IMPORTANCE Streptococcus pyogenes causes a wide variety of diseases, ranging from superficial skin and throat infections to life-threatening invasive infections. To establish these various disease manifestations, Streptococcus pyogenes requires tightly coordinated production of its virulence factor repertoire. Here, the response regulator CovR plays a crucial role. As an OmpR/PhoB family member, CovR is activated by phosphorylation on a conserved aspartate residue, leading to protein dimerization and subsequent binding to operator sites. Our transcriptome analysis using the monomeric phosphorylation mimic mutant CovR-D53E broadens this general notion by revealing dimerization-independent repression of a subset of CovR-regulated genes. Combined with promoter analyses, these data suggest distinct mechanisms of CovR transcriptional control, which allow for differential expression of virulence genes in response to environmental cues.

scholarly journals relA-Independent Amino Acid Starvation Response Network of Streptococcus pyogenes

2001 ◽  
Vol 183 (24) ◽  
pp. 7354-7364 ◽  
Author(s):  
Kerstin Steiner ◽  
Horst Malke
Keyword(s):  
Amino Acid ◽  
Streptococcus Pyogenes ◽  
Target Genes ◽  
Group A Streptococcus ◽  
Housekeeping Genes ◽  
Trna Synthetase ◽  
Amino Acid Starvation ◽  
Infection Process ◽  
Starvation Response ◽  
Virulence Gene Expression

ABSTRACT Streptococcus pyogenes (group A streptococcus [GAS]), a multiple-amino-acid-auxotrophic human pathogen, may face starvation for essential amino acids during various stages of the infection process. Since the response of GAS to such conditions is likely to influence pathogenetic processes, we set out to identify by transcriptional analyses genes and operons that are responsive to amino acid starvation and examined whether functionally meaningful response patterns can be ascertained. We discovered that GAS are capable of mounting a relA-independent amino acid starvation response that involves transcriptional modulation of a wide array of housekeeping genes as well as accessory and dedicated virulence genes. Housekeeping genes that were upregulated during starvation of both wild-type and relA mutant strains included the newly identified T-box members of the aminoacyl-tRNA synthetase genes, the genes for components of the tmRNA-mediated peptide tagging and proteolysis system for abnormal proteins (ssrA, smpB,clpP, and clpC), and the operons for thednaK and groE groups of molecular chaperones. In addition to upregulation of the genes for oligopeptide permease (opp), intracellular peptidase (pepB), and the two-component regulatorcovRS reported previously (K. Steiner and H. Malke, Mol. Microbiol. 38:1004–1016, 2000), amino acid starvation stimulated the transcription of the growth phase-associated, virulence-regulatory fas operon, the streptolysin S operon (sag), and the gene for autoinducer-2 production protein (luxS). A prominent feature of operons exhibiting internal transcriptional termination (opp, fas, andsag) was starvation-promoted full-length transcription, a mechanism that improves the efficacy of these systems by increasing the level of coordinate transcription of functionally related genes. Based on these results, a regulatory network with feedback mechanisms is proposed that counteracts the stringent response, links the levels of key rate-limiting enzymes to virulence gene expression, and enables the organism in a dynamic way to take advantage of protein-rich environments provided by its human host. As several of the affected target genes are controlled by more than one regulator, fine modulation may result in accordance with the demands imposed by ecologically different colonization sites upon the adaptive capacity of the pathogen.

scholarly journals Streptococcus pyogenes CovRS Mediates Growth in Iron Starvation and in the Presence of the Human Cationic Antimicrobial Peptide LL-37

2008 ◽  
Vol 191 (2) ◽  
pp. 673-677 ◽  
Author(s):  
Barbara J. Froehlich ◽  
Christopher Bates ◽  
June R. Scott
Keyword(s):  
Signal Transduction ◽  
Antimicrobial Peptide ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Signal Transduction System ◽  
Iron Starvation ◽  
Cationic Antimicrobial Peptide ◽  
Two Component ◽  
Group A ◽  
Two Component Signal Transduction

ABSTRACT We found that the global regulatory two-component signal transduction system CovRS mediates the ability of group A streptococcus (GAS) to grow under two stresses encountered during infection: iron starvation and the presence of LL-37. We also showed that CovRS regulates transcription of the multimetal transporter operon that is important for GAS growth in a low concentration of iron.

scholarly journals Role for sagA and siaA in Quorum Sensing and Iron Regulation in Streptococcus pyogenes

2007 ◽  
Vol 75 (10) ◽  
pp. 5011-5017 ◽  
Author(s):  
Kowthar Y. Salim ◽  
Joyce C. de Azavedo ◽  
Darrin J. Bast ◽  
Dennis G. Cvitkovitch
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Pyogenes ◽  
Iron Acquisition ◽  
Virulence Gene ◽  
Wild Type ◽  
Virulence Gene Expression ◽  
Streptolysin S ◽  
Wide Range ◽  
Cell Densities ◽  
The Many

ABSTRACT Streptococcus pyogenes is a ubiquitous and versatile pathogen that causes a variety of infections with a wide range of severity. The versatility of this organism is due in part to its capacity to regulate virulence gene expression in response to the many environments that it encounters during an infection. We analyzed the expression of two potential virulence factors, sagA and siaA (also referred to as pel and htsA, respectively), in response to conditions of varying cell densities and iron concentrations. The sagA gene was up-regulated in conditioned medium from a wild-type strain but not from sagA-deficient mutants, and the gene was also up-regulated in the presence of streptolysin S (SLS), the gene product of sagA, thus indicating that this gene or its product is involved in density-dependent regulation of S. pyogenes. By comparison, siaA responded in a manner consistent with a role in iron acquisition since it was up-regulated under iron-restricted conditions. Although siaA expression was also up-regulated in the presence of SLS and in conditioned media from both wild-type and sagA-deficient mutants, this up-regulation was not growth phase dependent. We conclude that sagA encodes a quorum-sensing signaling molecule, likely SLS, and further support the notion that siaA is likely involved in iron acquisition.

scholarly journals Virulence Gene Regulation by CvfA, a Putative RNase: the CvfA-Enolase Complex in Streptococcus pyogenes Links Nutritional Stress, Growth-Phase Control, and Virulence Gene Expression

2010 ◽  
Vol 78 (6) ◽  
pp. 2754-2767 ◽  
Author(s):  
Song Ok Kang ◽  
Michael G. Caparon ◽  
Kyu Hong Cho
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Nutritional Status ◽  
Streptococcus Pyogenes ◽  
Growth Phase ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Nutritional Stress ◽  
Altered Expression ◽  
Virulence Gene Expression

ABSTRACT Streptococcus pyogenes, a multiple-auxotrophic human pathogen, regulates virulence gene expression according to nutritional availability during various stages in the infection process or in different infection sites. We discovered that CvfA influenced the expression of virulence genes according to growth phase and nutritional status. The influence of CvfA in C medium, rich in peptides and poor in carbohydrates, was most pronounced at the stationary phase. Under these conditions, up to 30% of the transcriptome exhibited altered expression; the levels of expression of multiple virulence genes were altered, including the genes encoding streptokinase, CAMP factor, streptolysin O, M protein (more abundant in the CvfA− mutant), SpeB, mitogenic factor, and streptolysin S (less abundant). The increase of carbohydrates or peptides in media restored the levels of expression of the virulence genes in the CvfA− mutant to wild-type levels (emm, ska, and cfa by carbohydrates; speB by peptides). Even though the regulation of gene expression dependent on nutritional stress is commonly linked to the stringent response, the levels of ppGpp were not altered by deletion of cvfA. Instead, CvfA interacted with enolase, implying that CvfA, a putative RNase, controls the transcript decay rates of virulence factors or their regulators according to nutritional status. The virulence of CvfA− mutants was highly attenuated in murine models, indicating that CvfA-mediated gene regulation is necessary for the pathogenesis of S. pyogenes. Taken together, the CvfA-enolase complex in S. pyogenes is involved in the regulation of virulence gene expression by controlling RNA degradation according to nutritional stress.

scholarly journals LL-37 Triggers Formation of Streptococcus pyogenes Extracellular Vesicle-Like Structures with Immune Stimulatory Properties

2015 ◽  
Vol 8 (3) ◽  
pp. 243-257 ◽  
Author(s):  
Julia Uhlmann ◽  
Manfred Rohde ◽  
Nikolai Siemens ◽  
Bernd Kreikemeyer ◽  
Peter Bergman ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Inflammatory Responses ◽  
Virulence Gene ◽  
Antimicrobial Effect ◽  
Extracellular Vesicle ◽  
Bactericidal Effect ◽  
Virulence Gene Expression ◽  
Bacterial Surface ◽  
Bacterial Cultures ◽  
Potential Factor

Reports have shown that the antimicrobial peptide LL-37 is abundantly expressed but has limited bactericidal effect in Streptococcus pyogenes infections. At sub-inhibitory concentrations, LL-37 has been reported to alter virulence gene expression. Here, we explored the interaction of S. pyogenes strains with LL-37, focusing on bacterial growth, cell surface alterations and pro-inflammatory responses. Bioscreen turbidity measurements of strain 5448 cultured in the presence or absence of LL-37 confirmed the poor antimicrobial effect, and revealed a significant increase in turbidity of bacterial cultures exposed to sub-inhibitory concentrations of LL-37. However, this was not linked to increased bacterial counts. Electron microscopy of LL-37-exposed bacteria revealed the presence of vesicle-like structures on the bacterial surface. The vesicles stained positive for LL-37 and were released from the bacterial surface. Concentrated supernatants enriched in these structures had a broader protein content, including several virulence factors, compared to supernatants from untreated bacteria. The supernatants from LL-37-exposed bacteria were pro-inflammatory and elicited resistin and myeloperoxidase release from neutrophils. This is the first report on S. pyogenes extracellular vesicle-like structures formed at the bacterial surface in response to LL-37. The associated increased pro-inflammatory activity further implicates LL-37 as a potential factor involved in S. pyogenes pathogenesis.

scholarly journals Sequence Variations within PrfA DNA Binding Sites and Effects on Listeria monocytogenes Virulence Gene Expression

2000 ◽  
Vol 182 (3) ◽  
pp. 837-841 ◽  
Author(s):  
James R. Williams ◽  
Chetna Thayyullathil ◽  
Nancy E. Freitag
Keyword(s):  
Gene Expression ◽  
Listeria Monocytogenes ◽  
Dna Binding ◽  
Binding Sites ◽  
Virulence Genes ◽  
Regulation Of Gene Expression ◽  
Virulence Gene ◽  
Virulence Gene Expression ◽  
Dna Binding Sites ◽  
Sequence Variations

ABSTRACT Reporter gene fusions were used to investigate the contributions of PrfA DNA binding sites to Listeria monocytogenes virulence gene expression. Our results suggest that the DNA sequence of PrfA binding sites determines the levels of expression of certain virulence genes, such as hly and mpl. Other virulence genes, such as actA and plcB, may depend upon additional factors for full regulation of gene expression.

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