Dataset Information

Inter- and intraserotypic variation in the Streptococcus pyogenes Rgg regulon.

ABSTRACT: Human isolates of Streptococcus pyogenes, a Gram-positive bacterium, are characterized by significant genetic and phenotypic variation. The rgg locus, also known as ropB, is a global transcriptional regulator of genes associated with metabolism, stress responses, and virulence in S. pyogenes strain NZ131 (serotype M49). To assess the breadth of the Rgg regulon, the rgg gene was inactivated in three additional strains representing serotypes M1 (strains SF370 and MGAS5005) and M49 (strain CS101). Changes in gene expression were identified in the postexponential phase of growth using Affymetrix NimbleExpress Arrays. The results identified an Rgg core-regulon consisting of speB and adjacent hypothetical protein gene, spy2040, and a variable and strain-specific subregulon, ranging in size from a single gene (spy1793) in strain MGAS5005 to 43 genes in strain SF370. Thus, both interserotypic and intraserotypic variation is characteristic of the Rgg regulon in S. pyogenes.

SUBMITTER: Dmitriev AV

PROVIDER: S-EPMC2561273 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature

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Inter- and intraserotypic variation in the Streptococcus pyogenes Rgg regulon.

Dmitriev Alexander V AV McDowell Emily J EJ Chaussee Michael S MS

FEMS microbiology letters 20080701 1

Human isolates of Streptococcus pyogenes, a Gram-positive bacterium, are characterized by significant genetic and phenotypic variation. The rgg locus, also known as ropB, is a global transcriptional regulator of genes associated with metabolism, stress responses, and virulence in S. pyogenes strain NZ131 (serotype M49). To assess the breadth of the Rgg regulon, the rgg gene was inactivated in three additional strains representing serotypes M1 (strains SF370 and MGAS5005) and M49 (strain CS101). ...[more]

PMID: 18479433

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Project description:Recent studies have established the fact that multiple members of the Rgg family of transcriptional regulators serve as key components of quorum sensing (QS) pathways that utilize peptides as intercellular signaling molecules. We previously described a novel QS system in Streptococcus pyogenes which utilizes two Rgg-family regulators (Rgg2 and Rgg3) that respond to neighboring signaling peptides (SHP2 and SHP3) to control gene expression and biofilm formation. We have shown that Rgg2 is a transcriptional activator of target genes, whereas Rgg3 represses expression of these genes, and that SHPs function to activate the QS system. The mechanisms by which Rgg proteins regulate both QS-dependent and QS-independent processes remain poorly defined; thus, we sought to further elucidate how Rgg2 and Rgg3 mediate gene regulation. Here we provide evidence that S. pyogenes employs a unique mechanism of direct competition between the antagonistic, peptide-responsive proteins Rgg2 and Rgg3 for binding at target promoters. The highly conserved, shared binding sites for Rgg2 and Rgg3 are located proximal to the -35 nucleotide in the target promoters, and the direct competition between the two regulators results in concentration-dependent, exclusive occupation of the target promoters that can be skewed in favor of Rgg2 in vitro by the presence of SHP. These results suggest that exclusionary binding of target promoters by Rgg3 may prevent Rgg2 binding under SHP-limiting conditions, thereby preventing premature induction of the quorum sensing circuit. Rgg-family transcriptional regulators are widespread among low-G+C Gram-positive bacteria and in many cases contribute to bacterial physiology and virulence. Only recently was it discovered that several Rgg proteins function in cell-to-cell communication (quorum sensing [QS]) via direct interaction with signaling peptides. The mechanism(s) by which Rgg proteins mediate regulation is poorly understood, and further insight into Rgg function is anticipated to be of great importance for the understanding of both regulatory-network architecture and intercellular communication in Rgg-containing species. The results of this study on the Rgg2/3 QS circuit of S. pyogenes demonstrate that DNA binding of target promoters by the activator Rgg2 is directly inhibited by competitive binding by the repressor Rgg3, thereby preventing transcriptional activation of the target genes and premature induction of the QS circuit. This is a unique regulatory mechanism among Rgg proteins and other peptide-responsive QS regulators.

Dataset Information

Inter- and intraserotypic variation in the Streptococcus pyogenes Rgg regulon.

Publications

Inter- and intraserotypic variation in the Streptococcus pyogenes Rgg regulon.

Similar Datasets

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