Elucidating the CodY regulon in Staphylococcus aureus USA300 lineage using ChIPexo
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ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE163312 | GEO | 2022/08/29
REPOSITORIES: GEO
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Project description:CodY is a highly conserved global transcriptional factor that regulates the expression of dozens of genes related to metabolism and virulence in Staphylococcus aureus. The S. aureus CodY regulon has been studied in vitro. However, in vivo CodY DNA-binding activity and the identity of the corresponding target genes remain unknown due to lack of a ChIP-grade monoclonal antibody. Using a novel CodY monoclonal antibody that we developed in established ChIP-exo protocols, we report in vivo target genes of CodY in two S. aureus USA300 clinical strains (TCH1516 and LAC). The total number of CodY-binding sites exceeded 110, but their location varied between the two strains. The majority of the identified binding sites were located within the promoter regions. Based on the sequences of the CodY-binding sites, a model of CodY interaction with DNA is proposed. Furthermore, S. aureus CodY protein is highly conserved across a G+C Gram-positive species, including Bacillus subtilis and Listeria monocytogenes, and thus this study paves the way for exploration of the differential binding of CodY among a range of gram-positive species, including pathogenic ones
2021-08-17 | GSE159856 | GEO
Project description:More than 200 direct CodY target genes in Staphylococcus aureus were identified by genome-wide analysis of in vitro DNA binding. This analysis, which was confirmed for some genes by DNase I footprinting assays, revealed that CodY is a direct regulator of numerous transcription units associated with amino acid biosynthesis, transport of macromolecules and virulence. The virulence genes regulated by CodY fell into three groups. One group was dependent on the Agr system for its expression; these genes were indirectly regulated by CodY through its repression of the agr locus. A second group was regulated directly by CodY. The third group, which includes genes for alpha-toxin and capsule synthesis, was regulated by CodY in two ways, i.e., by direct repression and by repression of the agr locus. Since S. aureus CodY was activated in vitro by the branched chain amino acids and GTP, CodY appears to link changes in intracellular metabolite pools with the induction of numerous adaptive responses, including virulence. Affymetrix GeneChips were used to compare the transcript titers of S. aureus strains UAMS-1 (wild type) and corresponding agr- (strain CM18), codY- (strain MS1), and agr- codY- (strain CM19) isogenic mutant strains during exponential and stationary phase growth. At least two biological replicates were assessed for each strain and each growth phase.
2010-04-13 | E-GEOD-20973 | biostudies-arrayexpress
Project description:CodY is a conserved regulator in gram-positive organisms described to repress metabolic genes mainly involved in nitrogen metabolism but also to control the expression of virulence genes in pathogens. We constructed codY gene-replacement mutants in three unrelated S. aureus strains (Newman, UAMS-1, RN1HG). codY mutants grew slower in a chemically defined medium compared to the wild type strains. However, only codY mutants were able to grow in medium lacking threonine. Excess of isoleucine resulted in growth inhibition in the wild type but not in the codY mutants indicating a role of isoleucine for CodY dependent repression of metabolic genes. The prototypic CodY-repressed operon ilvDBCleuABCilvA is preceded by a CodY-binding motif and repressed after up-shift with isoleucine and to a lesser extent guanidine. Transcription of the quorum sensing system agr followed a similar expression pattern. The codY dependent repression of agr is in line with the concomitant influence of CodY on typical agr regulated genes such as cap, spa fnbA and coa. However, transcriptional analysis revealed that most of these virulence genes (e.g. cap, fnbA, spa hla) are also regulated by CodY in an agr negative background. Microarray analysis revealed the large majority of codY-repressed genes are involved in amino-acid transport and metabolism, genes showing codY dependent activation were mainly involved in nucleotide transport and metabolism or virulence. In summary, CodY in S. aureus not only acts as repressor for genes involved in nitrogen metabolism but also contributes to virulence gene regulation by supporting as well as substituting agr function.
2008-11-07 | GSE12340 | GEO
Project description:CodY is a conserved regulator in gram-positive organisms described to repress metabolic genes mainly involved in nitrogen metabolism but also to control the expression of virulence genes in pathogens. We constructed codY gene-replacement mutants in three unrelated S. aureus strains (Newman, UAMS-1, RN1HG). codY mutants grew slower in a chemically defined medium compared to the wild type strains. However, only codY mutants were able to grow in medium lacking threonine. Excess of isoleucine resulted in growth inhibition in the wild type but not in the codY mutants indicating a role of isoleucine for CodY dependent repression of metabolic genes. The prototypic CodY-repressed operon ilvDBCleuABCilvA is preceded by a CodY-binding motif and repressed after up-shift with isoleucine and to a lesser extent guanidine. Transcription of the quorum sensing system agr followed a similar expression pattern. The codY dependent repression of agr is in line with the concomitant influence of CodY on typical agr regulated genes such as cap, spa fnbA and coa. However, transcriptional analysis revealed that most of these virulence genes (e.g. cap, fnbA, spa hla) are also regulated by CodY in an agr negative background. Microarray analysis revealed the large majority of codY-repressed genes are involved in amino-acid transport and metabolism, genes showing codY dependent activation were mainly involved in nucleotide transport and metabolism or virulence. In summary, CodY in S. aureus not only acts as repressor for genes involved in nitrogen metabolism but also contributes to virulence gene regulation by supporting as well as substituting agr function. The microarray was manufactured by in situ synthesis of 10'807 long oligonucleotide probes , selected as previously described (Charbonnier, 2005). It covers >98% of all ORFs annotated in strains N315 and Mu50 , MW2, COL , NCTC8325, USA300 , MRSA252 an MSSA476 including their respective plasmids.
2008-11-06 | E-GEOD-12340 | biostudies-arrayexpress
Project description:The stringent response is initiated by rapid (p)ppGpp synthesis, which leads to a profound reprogramming of gene expression in most bacteria. The stringent phenotype seems to be species specific and may be mediated by fundamentally different molecular mechanisms. In Staphylococcus aureus, (p)ppGpp synthesis upon amino acid deprivation is achieved through the synthase domain of the bifunctional enzyme RSH (RelA/SpoT homolog). In several firmicutes, a direct link between stringent response and the CodY regulon was proposed. Wild-type strain HG001, rshSyn, codY and rshSyn, codY double mutants were analyzed by transcriptome analysis to delineate different consequences of RSH-dependent (p)ppGpp synthesis after induction of the stringent response by amino-acid deprivation. Under these conditions genes coding for major components of the protein synthesis machinery and nucleotide metabolism were down-regulated only in rsh positive strains. Genes which became activated upon (p)ppGpp induction are mostly regulated indirectly via de-repression of the GTP-responsive repressor CodY. Only seven genes, including those coding for the cytotoxic phenol-soluble modulins (PSMs), were found to be up-regulated via RSH independently of CodY. qtRT-PCR analyses of hallmark genes of the stringent response indicate that an RSH activating stringent condition is induced after uptake of S. aureus in human polymorphonuclear neutrophils (PMNs). The RSH activity in turn is crucial for intracellular expression of psms. Accordingly, rshSyn and rshSyn, codY mutants were less able to survive after phagocytosis similar to psm mutants. Intraphagosomal induction of psma1-4 and/or psmM-CM-^_1,2 could complement the survival of the rshSyn mutant. Thus, an active RSH synthase is required for intracellular psm expression which contributes to survival after phagocytosis. Microarray was used to evaluate alteration in the transcriptome of codY and rsh mutants and compared to the wild type
2013-04-05 | E-GEOD-45617 | biostudies-arrayexpress
Project description:CodY is a nutritional regulator mainly involved in amino acid metabolism. It has been extensively studied in Bacillis subtilis and Lactococcus lactis. We investigated the role of CodY in gene regulation and virulence of the human pathogen Streptococcus pneumoniae. We constructed a codY-mutant and examined the effect on gene and protein expression by microarray and 2D DIGE analysis. The pneumococcal CodY-regulon was found to consist predominantly of genes involved in amino acid metabolism, but also several other cellular processes, such as carbon metabolism and iron uptake. By means of electrophoretic mobility shift assays and DNA footprinting, we showed that most targets identified are under direct control of CodY. By mutating DNA predicted to represent the CodY-box based on the L. lactis consensus, we demonstrated that this sequence is indeed required for in vitro DNA-binding to target promoters. Similar to L. lactis, DNA-binding of CodY was enhanced in the presence of the branched chain amino acids isoleucine, leucine, and valine, and not by GTP. We observed in experimental mouse models that CodY is transcribed in the murine nasopharynx and lungs, and is specifically required for colonization. This finding was underscored by the diminished ability of the codY-mutant to adhere to nasopharyngeal cells in vitro. In conclusion, pneumococcal CodY predominantly regulates genes involved in amino acid metabolism and contributes to the early stages of infection, i.e. colonization of the nasopharynx. Keywords: codY CodY of Streptococcus pneumoniae: link between nutritional gene regulation and virulence
2010-05-25 | E-GEOD-7350 | biostudies-arrayexpress
Project description:CodY is a nutritional regulator mainly involved in amino acid metabolism. It has been extensively studied in Bacillis subtilis and Lactococcus lactis. We investigated the role of CodY in gene regulation and virulence of the human pathogen Streptococcus pneumoniae. We constructed a codY-mutant and examined the effect on gene and protein expression by microarray and 2D DIGE analysis. The pneumococcal CodY-regulon was found to consist predominantly of genes involved in amino acid metabolism, but also several other cellular processes, such as carbon metabolism and iron uptake. By means of electrophoretic mobility shift assays and DNA footprinting, we showed that most targets identified are under direct control of CodY. By mutating DNA predicted to represent the CodY-box based on the L. lactis consensus, we demonstrated that this sequence is indeed required for in vitro DNA-binding to target promoters. Similar to L. lactis, DNA-binding of CodY was enhanced in the presence of the branched chain amino acids isoleucine, leucine, and valine, and not by GTP. We observed in experimental mouse models that CodY is transcribed in the murine nasopharynx and lungs, and is specifically required for colonization. This finding was underscored by the diminished ability of the codY-mutant to adhere to nasopharyngeal cells in vitro. In conclusion, pneumococcal CodY predominantly regulates genes involved in amino acid metabolism and contributes to the early stages of infection, i.e. colonization of the nasopharynx. Keywords: codY
2007-11-20 | GSE7350 | GEO
Project description:The stringent response is initiated by rapid (p)ppGpp synthesis, which leads to a profound reprogramming of gene expression in most bacteria. The stringent phenotype seems to be species specific and may be mediated by fundamentally different molecular mechanisms. In Staphylococcus aureus, (p)ppGpp synthesis upon amino acid deprivation is achieved through the synthase domain of the bifunctional enzyme RSH (RelA/SpoT homolog). In several firmicutes, a direct link between stringent response and the CodY regulon was proposed. Wild-type strain HG001, rshSyn, codY and rshSyn, codY double mutants were analyzed by transcriptome analysis to delineate different consequences of RSH-dependent (p)ppGpp synthesis after induction of the stringent response by amino-acid deprivation. Under these conditions genes coding for major components of the protein synthesis machinery and nucleotide metabolism were down-regulated only in rsh positive strains. Genes which became activated upon (p)ppGpp induction are mostly regulated indirectly via de-repression of the GTP-responsive repressor CodY. Only seven genes, including those coding for the cytotoxic phenol-soluble modulins (PSMs), were found to be up-regulated via RSH independently of CodY. qtRT-PCR analyses of hallmark genes of the stringent response indicate that an RSH activating stringent condition is induced after uptake of S. aureus in human polymorphonuclear neutrophils (PMNs). The RSH activity in turn is crucial for intracellular expression of psms. Accordingly, rshSyn and rshSyn, codY mutants were less able to survive after phagocytosis similar to psm mutants. Intraphagosomal induction of psma1-4 and/or psmß1,2 could complement the survival of the rshSyn mutant. Thus, an active RSH synthase is required for intracellular psm expression which contributes to survival after phagocytosis.
2013-04-05 | GSE45617 | GEO
Project description:More than 200 direct CodY target genes in Staphylococcus aureus were identified by genome-wide analysis of in vitro DNA binding. This analysis, which was confirmed for some genes by DNase I footprinting assays, revealed that CodY is a direct regulator of numerous transcription units associated with amino acid biosynthesis, transport of macromolecules and virulence. The virulence genes regulated by CodY fell into three groups. One group was dependent on the Agr system for its expression; these genes were indirectly regulated by CodY through its repression of the agr locus. A second group was regulated directly by CodY. The third group, which includes genes for alpha-toxin and capsule synthesis, was regulated by CodY in two ways, i.e., by direct repression and by repression of the agr locus. Since S. aureus CodY was activated in vitro by the branched chain amino acids and GTP, CodY appears to link changes in intracellular metabolite pools with the induction of numerous adaptive responses, including virulence.
2010-04-01 | GSE20973 | GEO
Project description:Regulons for many transcription factors have been elucidated in model strains leading to an understanding of their role in producing physiological states. Comparative analysis of a regulon and its target genes between different strains of the same species is lacking. Ferric uptake regulator (Fur), involved in iron homeostasis, is one of the most conserved TFs, and is present in a wide range of bacteria. Using ChIP-exo experiments, we performed a comprehensive study of Fur binding sites in nine Escherichia coli strains with different lifestyles. 79 of the 431 target genes (18%) found belong to Fur’s core regulon, comprising genes involved in ion transport and metabolism, energy production and conversion, and amino acid metabolism and transport. 179 of the target genes (42%) comprise the accessory regulon, most of which were related to cell wall structure and biogenesis, and virulence factor pathways. The remaining target genes (173 or 40%) were in the unique regulon, with gene functions that were largely unknown. Furthermore, deletion of the fur gene led to distinct phenotypes in growth, motility, antibiotic resistance, and siderophore production. These results provide a more complete understanding of how Fur regulates a set of target genes with surprising variation in closely related bacteria.
2023-08-04 | GSE150240 | GEO