Two DNA‐binding domains of Mga are required for virulence gene activation in the group A streptococcus

McIver, Kevin S.; Myles, Rhonda L.

doi:10.1046/j.1365-2958.2002.02849.x

Cited by 68 publications

(99 citation statements)

References 58 publications

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“…For instance, among the cyanobacteria, some, but not all of the genes of the C i stimulon (McGinn et al, 2003;Wang et al, 2004) are regulated by CcmR (previously called NdhR), a LysR family regulator. In Gram-positive bacteria, regulators of the LysR family (Koehler, 2002) and regulator families such as the two-component signal-transducing systems (Federle et al, 1999;McIver & Myles, 2002) have been described. Thus, the C i response regulation in L. plantarum may also involve several families of regulators, as found with other bacteria.…”

Section: Discussionmentioning

confidence: 99%

Lactobacillus plantarum response to inorganic carbon concentrations: PyrR2-dependent and -independent transcription regulation of genes involved in arginine and nucleotide metabolism

Bringel

Hammann²,

Kugler

et al. 2008

Microbiology

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Lactobacillus plantarum susbp. plantarum is a capnophilic Gram-positive heterotroph with optimal growth in 4 % CO 2 -enriched air. At low inorganic carbon (C i ) concentrations, the pyr genes encoding the enzymes of the pyrimidine biosynthetic pathway were overexpressed, in agreement with a previous study showing that these genes are regulated at the transcription level in response to C i via a PyrR 2 -mediated mechanism. A previous study of high-CO 2 -requiring (HCR) mutants revealed an unknown genetic link between arginine regulation and C i -dependent nutritional needs. To better understand L. plantarum's adaptation to C i availability, additional C iresponsive genes were sought in the arginine biosynthetic pathway (arg and car genes) using slot-blot hybridization and a proteomic differential 2D gel electrophoresis (DIGE) global approach. Besides the nine pyr-encoded proteins, 16 new Icr (inorganic-carbon-regulated) proteins accumulated differentially in response to C i availability, suggesting that the C i response involves several metabolic pathways and adaptation processes. Among these Icr proteins only argininosuccinate lyase, encoded by argH, was involved in arginine biosynthesis. Three proteins involved in the purine biosynthetic pathway and nucleotide conversion, adenylate kinase (Adk), GMP synthase (GuaA), and IMP dehydrogenase (GuaB), accumulated differentially in response to changes in C i levels. Expression of the Icr protein-encoding genes argH and guaB was regulated at the transcription level or by RNA stability in response to C i availability, as previously demonstrated for the pyr genes. However, PyrR 2 was not essential for the C i -regulated transcription of argH and guaB, demonstrating that PyrR 2 modulates only a subset of C i -regulated genes. These results suggest that the C i response may involve at least two regulatory mechanisms in L. plantarum.

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Section: Discussionmentioning

confidence: 99%

Lactobacillus plantarum response to inorganic carbon concentrations: PyrR2-dependent and -independent transcription regulation of genes involved in arginine and nucleotide metabolism

Bringel

Hammann²,

Kugler

et al. 2008

Microbiology

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“…Before use, the membranes were screened ECL to ensure no residual signals were present. Whole cell and extracellular surface streptococcal proteins were isolated as previously described (McIver and Myles, 2002).…”

Section: Immunoblot Analysismentioning

confidence: 99%

Identification of pyruvate kinase as an antigen associated with Tourette syndrome

Kansy

Katsovich

McIver

et al. 2006

Journal of Neuroimmunology

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Immune responses to β-hemolytic streptococcal infections are hypothesized to trigger tic disorders and early-onset obsessive-compulsive disorder (OCD) in some pediatric populations. Here we identify the M1 isoform of the glycolytic enzyme, pyruvate kinase (PK) as an autoimmune target in Tourette syndrome and associated disorders. Antibodies to PK reacted strongly with surface antigens of infectious strains of streptococcus, and antibodies to streptococcal M proteins reacted with PK. Moreover, immunoreactivity to PK in patients with exacerbated symptoms who had recently acquired a streptococcal infection was 7-fold higher compared to patients with exacerbated symptoms and no evidence of a streptococcal infection. These data suggest that PK can function as an autoimmune target and that this immunoreactivity may be associated with Tourette syndrome, OCD, and associated disorders.

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“…Whole-cell GAS protein extractions were performed as previously described (16). Briefly, mid-logarithmic-phase GAS cultures were harvested by centrifugation and resuspended in saline containing 1ϫ complete protease inhibitor cocktail (Roche).…”

Section: Methodsmentioning

confidence: 99%

“…Proteins were analyzed by Western blot as previously described (16). Blots were incubated with either a 1:2,000 dilution of anti-His tag monoclonal antibody (Novagen) or a 1:1,000 dilution anti-Mga-pep2 antiserum (16), then incubated with a 1:25,000 dilution of either anti-mouse (Chemicon) or anti-rat (Santa Cruz Biotechnologies) horseradish peroxidase-conjugated secondary antibody, respectively, and visualized using the Western Lightning chemiluminescence system (Perkin Elmer). For a loading control, blots were stripped in a solution containing 2% sodium dodecyl sulfate, 50 mM dithiothreitol (DTT), and 50 mM Tris-HCl, pH 7.0, for 30 min at 70°C and reprobed with a 1:50,000 dilution of mouse anti-Hsp60 monoclonal antibody (StressGen Biotechnologies Corp.).…”

Section: Methodsmentioning

confidence: 99%

“…A serotype M6 Mga (mga-1) is able to activate transcription by interacting with specific DNA sites within regulated (Pemm, PscpA, and PsclA) and autoregulated (Pmga) promoters (1,14,18). Two amino-terminal helix-turnhelix (HTH) domains necessary for DNA binding and transcriptional activation were found in M6 Mga: one (HTH-4) that is absolutely essential for binding to all targets and a second (HTH-3) that serves an accessory role, primarily in autoregulation from Pmga (16). In addition, two amino acids involved in transcriptional activation of a divergent Mga (mga-2) have been identified (27).…”

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confidence: 99%

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Domains Required for Transcriptional Activation Show Conservation in the Mga Family of Virulence Gene Regulators

Vahling

McIver

2006

J Bacteriol

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Mga, or the multigene regulator of the group A streptococcus (GAS) (Streptococcus pyogenes), is a transcriptional regulator of virulence genes important for colonization and immune evasion. All serotypes of the GAS possess one of two divergent mga alleles (mga-1 or mga-2), and orthologues of Mga have also been identified in other pathogenic streptococci. To date, the only functional motifs established within Mga are two aminoterminal DNA-binding domains (HTH-3 and HTH-4). To uncover novel domains, a random mutagenesis screen using an M6 Mga (mga-1) was undertaken to find mutations leading to a defect in transcriptional activation of the Mga-regulated emm gene. In addition to mutations in the established DNA-binding domains, the screen also revealed mutations in a region conserved among several Mga orthologues. Alanine scanning helped resolve the boundaries of this conserved Mga domain (CMD-1) spanning from residues 10 to 15 of the protein, with the two flanking amino acid residues likely involved in protein stability. Transcriptional reporter analyses demonstrated the importance of CMD-1 for activation of Pemm and autoactivation of Pmga in the serotype M6 Mga. Mutational analyses showed that both CMD-1 and HTH-4 are also necessary for activation of the promoter target Pmrp in a divergent serotype M4 Mga (mga-2), suggesting a conserved functionality. However, in contrast to M6, the M4 Mga mutants did not show a defect in autoregulation. Mutation of similar conserved residues in the Mga-like regulator DmgB from S. dysgalactiae subsp. dysgalactiae showed that CMD-1 and HTH-4 are critical for transcriptional activation in this orthologue, implying that a common mechanism of virulence gene activation may exist for members of the Mga family of regulators.

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Two DNA‐binding domains of Mga are required for virulence gene activation in the group A streptococcus

Cited by 68 publications

References 58 publications

Lactobacillus plantarum response to inorganic carbon concentrations: PyrR2-dependent and -independent transcription regulation of genes involved in arginine and nucleotide metabolism

Lactobacillus plantarum response to inorganic carbon concentrations: PyrR2-dependent and -independent transcription regulation of genes involved in arginine and nucleotide metabolism

Identification of pyruvate kinase as an antigen associated with Tourette syndrome

Domains Required for Transcriptional Activation Show Conservation in the Mga Family of Virulence Gene Regulators

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