title: Counteractive balancing of transcriptome expression involving CodY and CovRS in Streptococcus pyogenes.
abstract: Streptococcus pyogenes (group A streptococcus [GAS]) responds to environmental changes in a manner that results in an adaptive regulation of the transcriptome. The objective of the present study was to understand how two global transcriptional regulators, CodY and CovRS, coordinate the transcriptional network in S. pyogenes. Results from expression microarray data and quantitative reverse transcription-PCR (qRT-PCR) showed that the global regulator CodY controls the expression of about 250 genes, or about 17% of the genome of strain NZ131. Additionally, the codY gene was shown to be negatively autoregulated, with its protein binding directly to the promoter region with a CodY binding site. In further studies, the influence of codY, covRS, and codY-covRS mutations on gene expression was analyzed in growth phase-dependent conditions using C medium, reported to mimic nutritional abundance and famine conditions similar to those found during host GAS infection. Additional biological experiments of several virulence phenotypes, including pilin production, biofilm formation, and NAD glycohydrolase activity, demonstrated the role that both CodY and CovRS play in their regulation. Correlation analysis of the overall data revealed that, in exponentially growing cells, CodY and CovRS act in opposite directions, with CodY stimulating and CovRS repressing a substantial fraction of the core genome, including many virulence factors. This is the first report of counteractive balancing of transcriptome expression by global transcription regulators and provides important insight into how GAS modulates gene expression by integrating important extracellular and intracellular information.
authors.affiliation: Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, BMSB 907, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA. JKreth@ouhsc.edu
authors.forename: Jens
authors.initials: J
authors.lastname: Kreth
authors.forename: Zhiyun
authors.initials: Z
authors.lastname: Chen
authors.forename: Joseph
authors.initials: J
authors.lastname: Ferretti
authors.forename: Horst
authors.initials: H
authors.lastname: Malke
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D000071677:Histidine Kinase; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009244:NAD+ Nucleosidase / Q000235:genetics / Q000378:metabolism; D040081:Protein Array Analysis / Q000379:methods; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015203:Reproducibility of Results; D013297:Streptococcus pyogenes / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C432143:CsrR protein, Streptococcus pyogenes; D047908:Intracellular Signaling Peptides and Proteins; D012097:Repressor Proteins; C534547:CovS protein, Streptococcus pyogenes; D000071677:Histidine Kinase; D009244:NAD+ Nucleosidase