Cell Membrane Maintenance by PhoP is Critical for Methyylglyoxal Resistance in Mycobacterium tuberculosis
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ABSTRACT:
ORGANISM(S): Mycobacterium tuberculosis
PROVIDER: GSE297704 | GEO | 2026/05/01
REPOSITORIES: GEO
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Project description:During Mycobacterium tuberculosis infections bacteria are engulfed by macrophages, a main line of defense against invading pathogens. Upon activation, macrophages increase glycolysis producing the antibacterial aldehyde methylglyoxal. To test if bacterial methylglyoxal resistance is required for robust infections, we sought to identify Mycobacterium tuberculosis defense mechanisms against methylglyoxal. We identified phoP mutants were among the most highly sensitive strains to methylglyoxal in vitro. phoP mutants are attenuated in mice but were even more attenuated in mice that accumulate methylglyoxal. We further found phoP bacilli exhibited increased membrane permeability and were more permeable to methylglyoxal. Suppressor mutations in the fatty acid Beta-oxidation genes fadE25 or fixB restored impermeability and resistance to methylglyoxal to a phoP mutant. Together, our data show that a major virulence role for PhoP is to provide Mycobacterium tuberculosis resistance to methylglyoxal toxicity in vivo by regulating cell envelope integrity. The mass spectrometry files supporting this hypothesis are deposited here.
2025-08-07 | MSV000098760 | MassIVE
Project description:The PhoPR two-component system is essential for virulence in Mycobacterium tuberculosis where it controls expression of approximately 2% of the genes, including those for the ESX-1 secretion apparatus, a major virulence determinant. Mutations in phoP lead to compromised production of pathogen-specific cell wall components and attenuation both ex vivo and in vivo. The PhoP regulon comprises several transcriptional regulators as well as genes for polyketide synthases and PE/PPE proteins. The most prominent site of PhoP regulation was located in the intergenic region between rv2395 and PE_PGRS41, where the mcr7 gene codes for a small non-coding RNA (ncRNA). Our prediction suggested that Mcr7 might regulate tatC at the post-transcriptional level by occlusion of the RBS and the consequent translational arrest. Consequently, we studied the secretome from exponentially grown cultures of strain H37Rv, its phoP mutant and a phoP complemented mutant by in-depth proteomics. The results are consistent with a regulatory model involving PhoP, Mcr7 and tatC mRNA since the absence of Mcr7 in the phoP mutant would result in more efficient TatC translation and therefore increased secretion.
2018-08-29 | PXD000698 | Pride
Project description:Following phagocytosis by macrophages, Mycobacterium tuberculosis (Mtb) senses the intracellular environment and remodels its gene expression for growth in the phagosome. Abramovitch et.al. in this current study identified an Acid and Phagosome Regulated (aprABC) locus that is unique to the Mtb complex and whose gene expression is induced during growth in acidic environments in vitro and in macrophages. The authors propose a model where phoP senses the acidic pH of the phagosome and induces aprABC expression to fine-tune processes unique for intracellular adaptation of Mtb complex bacteria. This study uses microarray analyses to compare transcriptional responses of wild type Mycobacterium tuberculosis (CDC1551) to aprABC locus deletion mutants and the phoP transposon mutant. The bacteria were grown to early log phase in vented T-75 standing flasks containing 12 mL of pH 7.0 7H9 OADC medium. Transcript levels of the wild type bacteria were compared to the following mutants: aprABC null, aprBC null, aprC null, phoP::Tn mutant.
2011-07-09 | E-GEOD-22854 | biostudies-arrayexpress
Project description:PhoP is considered a regulator of virulence despite being conserved in both pathogenic and non-pathogenic Enterobacteriaceae. While Escherichia coli strains represent both non-pathogenic commensal isolates and numerous virulent pathotypes, the PhoP virulence regulator has only been studied in commensal E. coli. To better understand how conserved transcription factors contribute to virulence, we characterized PhoP in pathogenic E. coli. Loss of phoP significantly attenuated E. coli during extraintestinal infection. This was not surprising since we demonstrated that PhoP differentially regulated the transcription of >600 genes. In addition to survival at acidic pH and resistance to polymyxin B, PhoP was required for repression of motility and oxygen-independent changes in the expression of primary dehydrogenase and terminal reductase respiratory chain components. All phenotypes have in common a reliance on an energized membrane. Thus, we hypothesized that PhoP mediated these effects by regulating genes that generate a proton motive force. Indeed, bacteria lacking PhoP exhibited a hyper-polarized membrane, and dissipation of the transmembrane electrochemical gradient increased the susceptibility of the phoP mutant to acidic pH, while inhibiting respiratory generation of the proton gradient restored resistance to antimicrobial peptides independent of lipopolysaccharide modification. These findings demonstrate a connection between PhoP, virulence, and the energized state of the membrane.
2011-07-29 | GSE31029 | GEO
Project description:The PhoPR two-component system is essential for virulence in Mycobacterium tuberculosis where it controls expression of approximately 2% of the genes, including those for the ESX-1 secretion apparatus, a major virulence determinant. Mutations in phoP lead to compromised production of pathogen-specific cell wall components and attenuation both ex vivo and in vivo. Using antibodies against the native protein in ChIP-seq experiments (chromatin immunoprecipitation followed by high-throughput sequencing) we demonstrated that PhoP binds to at least 35 loci on the M. tuberculosis genome. The PhoP regulon comprises several transcriptional regulators as well as genes for polyketide synthases and PE/PPE proteins. Integration of ChIP-seq results with high-resolution transcriptomic analysis (RNA-seq) revealed that PhoP controls 30 genes directly, whilst regulatory cascades are responsible for signal amplification and downstream effects. The most prominent site of PhoP regulation was located in the intergenic region between rv2395 and PE_PGRS41, where the mcr7 gene codes for a small non-coding RNA (ncRNA). Northern blot experiments confirmed the absence of Mcr7 in the M. tuberculosis phoP mutant as well as low-level expression of the ncRNA in M. tuberculosis complex members other than M. tuberculosis. By means of genetic and proteomic analyses we demonstrated that Mcr7 modulates translation of the tatC mRNA thereby impacting the activity of the Twin Arginine Translocation (Tat) protein secretion apparatus. As a result, secretion of the immunodominant Ag85 complex and the beta-lactamase BlaC is affected, among others. Mcr7, the first ncRNA of M. tuberculosis whose function has been established, therefore represents a missing link between the PhoPR two-component system and the downstream functions necessary for successful infection of the host.
2014-06-02 | GSE54240 | GEO
Project description:The PhoPR two-component system is essential for virulence in Mycobacterium tuberculosis where it controls expression of approximately 2% of the genes, including those for the ESX-1 secretion apparatus, a major virulence determinant. Mutations in phoP lead to compromised production of pathogen-specific cell wall components and attenuation both ex vivo and in vivo. Using antibodies against the native protein in ChIP-seq experiments (chromatin immunoprecipitation followed by high-throughput sequencing) we demonstrated that PhoP binds to at least 35 loci on the M. tuberculosis genome. The PhoP regulon comprises several transcriptional regulators as well as genes for polyketide synthases and PE/PPE proteins. Integration of ChIP-seq results with high-resolution transcriptomic analysis (RNA-seq) revealed that PhoP controls 30 genes directly, whilst regulatory cascades are responsible for signal amplification and downstream effects. The most prominent site of PhoP regulation was located in the intergenic region between rv2395 and PE_PGRS41, where the mcr7 gene codes for a small non-coding RNA (ncRNA). Northern blot experiments confirmed the absence of Mcr7 in the M. tuberculosis phoP mutant as well as low-level expression of the ncRNA in M. tuberculosis complex members other than M. tuberculosis. By means of genetic and proteomic analyses we demonstrated that Mcr7 modulates translation of the tatC mRNA thereby impacting the activity of the Twin Arginine Translocation (Tat) protein secretion apparatus. As a result, secretion of the immunodominant Ag85 complex and the beta-lactamase BlaC is affected, among others. Mcr7, the first ncRNA of M. tuberculosis whose function has been established, therefore represents a missing link between the PhoPR two-component system and the downstream functions necessary for successful infection of the host.
2014-06-02 | GSE54239 | GEO
Project description:The PhoPR two-component system is essential for virulence in Mycobacterium tuberculosis where it controls expression of approximately 2% of the genes, including those for the ESX-1 secretion apparatus, a major virulence determinant. Mutations in phoP lead to compromised production of pathogen-specific cell wall components and attenuation both ex vivo and in vivo. Using antibodies against the native protein in ChIP-seq experiments (chromatin immunoprecipitation followed by high-throughput sequencing) we demonstrated that PhoP binds to at least 35 loci on the M. tuberculosis genome. The PhoP regulon comprises several transcriptional regulators as well as genes for polyketide synthases and PE/PPE proteins. Integration of ChIP-seq results with high-resolution transcriptomic analysis (RNA-seq) revealed that PhoP controls 30 genes directly, whilst regulatory cascades are responsible for signal amplification and downstream effects. The most prominent site of PhoP regulation was located in the intergenic region between rv2395 and PE_PGRS41, where the mcr7 gene codes for a small non-coding RNA (ncRNA). Northern blot experiments confirmed the absence of Mcr7 in the M. tuberculosis phoP mutant as well as low-level expression of the ncRNA in M. tuberculosis complex members other than M. tuberculosis. By means of genetic and proteomic analyses we demonstrated that Mcr7 modulates translation of the tatC mRNA thereby impacting the activity of the Twin Arginine Translocation (Tat) protein secretion apparatus. As a result, secretion of the immunodominant Ag85 complex and the beta-lactamase BlaC is affected, among others. Mcr7, the first ncRNA of M. tuberculosis whose function has been established, therefore represents a missing link between the PhoPR two-component system and the downstream functions necessary for successful infection of the host. RNA-Seq: M. tuberculosis H37Rv (GC1237) cultures grown in vitro to exponential phase. One wild type sample plus one isogenic phoP mutant sample
2014-06-02 | E-GEOD-54240 | biostudies-arrayexpress
Project description:The PhoPR two-component system is essential for virulence in Mycobacterium tuberculosis where it controls expression of approximately 2% of the genes, including those for the ESX-1 secretion apparatus, a major virulence determinant. Mutations in phoP lead to compromised production of pathogen-specific cell wall components and attenuation both ex vivo and in vivo. Using antibodies against the native protein in ChIP-seq experiments (chromatin immunoprecipitation followed by high-throughput sequencing) we demonstrated that PhoP binds to at least 35 loci on the M. tuberculosis genome. The PhoP regulon comprises several transcriptional regulators as well as genes for polyketide synthases and PE/PPE proteins. Integration of ChIP-seq results with high-resolution transcriptomic analysis (RNA-seq) revealed that PhoP controls 30 genes directly, whilst regulatory cascades are responsible for signal amplification and downstream effects. The most prominent site of PhoP regulation was located in the intergenic region between rv2395 and PE_PGRS41, where the mcr7 gene codes for a small non-coding RNA (ncRNA). Northern blot experiments confirmed the absence of Mcr7 in the M. tuberculosis phoP mutant as well as low-level expression of the ncRNA in M. tuberculosis complex members other than M. tuberculosis. By means of genetic and proteomic analyses we demonstrated that Mcr7 modulates translation of the tatC mRNA thereby impacting the activity of the Twin Arginine Translocation (Tat) protein secretion apparatus. As a result, secretion of the immunodominant Ag85 complex and the beta-lactamase BlaC is affected, among others. Mcr7, the first ncRNA of M. tuberculosis whose function has been established, therefore represents a missing link between the PhoPR two-component system and the downstream functions necessary for successful infection of the host. ChiP-Seq: M. tuberculosis H37Rv (GC1237) cultures grown in vitro to exponential phase. Two wild type samples plus one isogenic phoP mutant as control
2014-06-02 | E-GEOD-54239 | biostudies-arrayexpress
Project description:PhoP is considered a regulator of virulence despite being conserved in both pathogenic and non-pathogenic Enterobacteriaceae. While Escherichia coli strains represent both non-pathogenic commensal isolates and numerous virulent pathotypes, the PhoP virulence regulator has only been studied in commensal E. coli. To better understand how conserved transcription factors contribute to virulence, we characterized PhoP in pathogenic E. coli. Loss of phoP significantly attenuated E. coli during extraintestinal infection. This was not surprising since we demonstrated that PhoP differentially regulated the transcription of >600 genes. In addition to survival at acidic pH and resistance to polymyxin B, PhoP was required for repression of motility and oxygen-independent changes in the expression of primary dehydrogenase and terminal reductase respiratory chain components. All phenotypes have in common a reliance on an energized membrane. Thus, we hypothesized that PhoP mediated these effects by regulating genes that generate a proton motive force. Indeed, bacteria lacking PhoP exhibited a hyper-polarized membrane, and dissipation of the transmembrane electrochemical gradient increased the susceptibility of the phoP mutant to acidic pH, while inhibiting respiratory generation of the proton gradient restored resistance to antimicrobial peptides independent of lipopolysaccharide modification. These findings demonstrate a connection between PhoP, virulence, and the energized state of the membrane. Comparison of gene expression between wild-type CFT073 and a CFT073 phoP deletion mutant during logarithmic phase growth in LB medium. Three biological replicates were compared from each strain.
2011-07-28 | E-GEOD-31029 | biostudies-arrayexpress
Project description:Following phagocytosis by macrophages, Mycobacterium tuberculosis (Mtb) senses the intracellular environment and remodels its gene expression for growth in the phagosome. Abramovitch et.al. in this current study identified an Acid and Phagosome Regulated (aprABC) locus that is unique to the Mtb complex and whose gene expression is induced during growth in acidic environments in vitro and in macrophages. The authors propose a model where phoP senses the acidic pH of the phagosome and induces aprABC expression to fine-tune processes unique for intracellular adaptation of Mtb complex bacteria.
2011-07-09 | GSE22854 | GEO