The critical role of DNA in the equilibrium between OmpR and phosphorylated OmpR mediated by EnvZ in Escherichiacoli

Qin, L.

doi:10.1073/pnas.031383098

Cited by 9 publications

(4 citation statements)

References 28 publications

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“…The only exception was that the OmpR TF family of pathogenic Leptospira species ( L. interrogans and L. borgpetersenii ), which was larger than that of L. biflexa . Considering that the OmpR TF was first defined as a regulator of outer membrane porin genes ( ompC and ompF ) in E. coli [78] , [79] , it is possible that the leptospiral OmpR TFs were also involved in the regulation of the porins or other membrane proteins. Pathogenic Leptospira may regulate OMPs more efficiently than non-pathogenic L. biflexa .…”

Section: Resultsmentioning

confidence: 99%

Transcriptional Responses of Leptospira interrogans to Host Innate Immunity: Significant Changes in Metabolism, Oxygen Tolerance, and Outer Membrane

Xue

Dong

et al. 2010

PLoS Negl Trop Dis

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Background Leptospira interrogans is the major causative agent of leptospirosis. Phagocytosis plays important roles in the innate immune responses to L. interrogans infection, and L. interrogans can evade the killing of phagocytes. However, little is known about the adaptation of L. interrogans during this process.Methodology/Principal FindingsTo better understand the interaction of pathogenic Leptospira and innate immunity, we employed microarray and comparative genomics analyzing the responses of L. interrogans to macrophage-derived cells. During this process, L. interrogans altered expressions of many genes involved in carbohydrate and lipid metabolism, energy production, signal transduction, transcription and translation, oxygen tolerance, and outer membrane proteins. Among them, the catalase gene expression was significantly up-regulated, suggesting it may contribute to resisting the oxidative pressure of the macrophages. The expressions of several major outer membrane protein (OMP) genes (e.g., ompL1, lipL32, lipL41, lipL48 and ompL47) were dramatically down-regulated (10–50 folds), consistent with previous observations that the major OMPs are differentially regulated in vivo. The persistent down-regulations of these major OMPs were validated by immunoblotting. Furthermore, to gain initial insight into the gene regulation mechanisms in L. interrogans, we re-defined the transcription factors (TFs) in the genome and identified the major OmpR TF gene (LB333) that is concurrently regulated with the major OMP genes, suggesting a potential role of LB333 in OMPs regulation.Conclusions/SignificanceThis is the first report on global responses of pathogenic Leptospira to innate immunity, which revealed that the down-regulation of the major OMPs may be an immune evasion strategy of L. interrogans, and a putative TF may be involved in governing these down-regulations. Alterations of the leptospiral OMPs up interaction with host antigen-presenting cells (APCs) provide critical information for selection of vaccine candidates. In addition, genome-wide annotation and comparative analysis of TFs set a foundation for further studying regulatory networks in Leptospira spp.

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Section: Resultsmentioning

confidence: 99%

Transcriptional Responses of Leptospira interrogans to Host Innate Immunity: Significant Changes in Metabolism, Oxygen Tolerance, and Outer Membrane

Xue

Dong

et al. 2010

PLoS Negl Trop Dis

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“…We chose to study the OmpR response regulator binding because it is a well-characterized protein and its target promoter regions are known in detail. ,,, In E. coli, OmpR and its cognate sensor kinase, EnvZ, control the expression of the outer membrane porin proteins, OmpC and OmpF. In response to changes in environmental osmotic pressure, OmpR binds in a hierarchical fashion to the promoter regions of the ompF and ompC genes. ,,, The promoter regions for the OmpF and OmpC proteins consist of multiple protein binding regions, designated F1, F2, F3, F4, and C1, C2, C3 (Figure A), each approximately twelve nucleotides long. Two OmpR molecules bind to each site and then interact with the alpha subunit of RNA polymerase to control transcription .…”

Section: Resultsmentioning

confidence: 99%

“…This form of the protein binds to high affinity sites on the ompF gene (F1, F2) and thus causes expression of the OmpF porin protein. As the osmotic pressure of the environment increases, the level of the phosphorylated form of the protein (OmpR-P) increases, and additional low affinity sites are occupied (C1, C2, C3, F3, and F4) as the protein becomes more active. ,, Binding to the low affinity F4 site results in transcriptional repression of the OmpF protein, while binding to the low affinity sites on the ompC gene results in transcriptional activation of the OmpC protein 1 Schematic presentations.…”

Section: Resultsmentioning

confidence: 99%

Surface Plasmon Resonance Imaging of Transcription Factor Proteins: Interactions of Bacterial Response Regulators with DNA Arrays on Gold Films

et al. 2002

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Surface plasmon resonance (SPR) imaging measurements have been used to study the sequence specific adsorption of response regulator proteins to DNA arrays constructed on gold thin films. Bacteria adapt to their environment primarily through two-component signal transduction systems that consist of an environmental sensor histidine kinase and a transcription activator response regulator DNA binding protein. DNA arrays were fabricated from oligonucleotide sequences of known DNA binding regions for two response regulators: OmpR, which controls gene expression of the outer membrane porin proteins in Escherichia coli, and VanR, which is involved in the antibiotic vancomycin resistance in Enterococcus faecium. The label-free method of SPR imaging was then used to monitor the sequence specific binding of these two response regulator proteins to the DNA arrays. The promoter regions from the ompF (F1 and F2) and ompC (C1) genes for the OmpR protein, and from the vanRS (R1) and vanHAX (H1 and H2) genes for the VanR protein were studied. SPR imaging was used to (i) monitor and compare the binding of both response regulators to various promoter regions on the DNA array, (ii) compare the binding of the OmpR response regulator protein in its phosphorylated and nonphosphorylated forms, and (iii) monitor the inhibition of VanR protein binding to the DNA arrays in the presence of a small molecule DNA binding inhibitor. The proteins exhibited specificity for the known binding sequences compared to control sequences on the DNA array. For the OmpR protein, the highest amount of binding was observed at the F1 site. When OmpR was phosphorylated by a small molecule phosphodonor, acetyl phosphate, there was on average a 42% increase in protein binding. In contrast, phosphorylated VanR binding decreased by an average of 40% in the presence of a known DNA binding inhibitor, (2,3,4-trifluorophenylisothiazolone). These measurements demonstrate that SPR imaging is an effective screening method for compounds that target DNA protein interactions and can serve as a useful tool for the discovery of new therapeutic molecules that target DNA binding proteins. † Part of the Langmuir special issue entitled The Biomolecular Interface.

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“…OmpF is the key ligand for susceptibility (8,42), but other genes have been identified that are requisite for susceptibility to MccPDI (ompR, atpA, atpF, atpE, atpH, dsbA, and dsbB [8]). OmpR regulates the expression of ompF as part of the EnvZ/OmpR two-component osmoregulatory system (42)(43)(44). The roles of ATP synthase (atpA, atpF, atpE, and atpH) and thiol-disulfide interchange protein (dsbA and dsbB) in MccPDI susceptibility remain unknown (8,(45)(46)(47).…”

Section: Discussionmentioning

confidence: 99%

Microcin PDI Inhibits Antibiotic-Resistant Strains of Escherichia coli and Shigella through a Mechanism of Membrane Disruption and Protection by Homotrimer Self-Immunity

Graça

Avillan

et al. 2019

Appl Environ Microbiol

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Microcin PDI (MccPDI), a class IIa microcin that is produced by Escherichia coli strains 25 and 284, is known to inhibit foodborne pathogenic enterohemorrhagic E. coli serotypes O157:H7 and O26. Here we demonstrate that MccPDI can inhibit Shigella strains and E. coli isolates that are multidrug resistant, the latter including strains known to cause urinary tract infections in people and companion animals. Two exceptions out of 17 strains were identified. One of the two resistant E. coli isolates (AR0349) has a mutation in a critical amino acid residue that was identified in previous work as a requisite for the MccPDI precursor protein (McpM) to interact with outer membrane porin F (OmpF) on susceptible cells. The second resistant E. coli strain (MAD 96) had no mutations in ompF, but it was PCR positive for two antimicrobial peptides, of which colicin Ia/Ib likely inhibits the MccPDI-producing strain during coculture. Recombinant McpM was still effective against strain MAD 96. In an assessment of how MccPDI affects susceptible strains, results from both an extracellular ATP assay and a nucleic acid staining assay were consistent with membrane damage, while the addition of 200-to 600-Da polyethylene glycol (PEG) to cocultures protected against MccPDI (Ͼ600-Da PEG did not provide protection). Further studies using a paraformaldehyde cross-linking experiment and a bacterial two-hybrid assay demonstrated that MccPDI immunity protein (McpI) forms a multimeric complex with itself and presumably protects the producer strain from within the periplasm through an unknown mechanism. IMPORTANCE Microcins represent potential alternatives to conventional antibiotics for human and veterinary medicine. For them to be applied in this manner, however, we need to better understand their spectrum of activity, how these proteins interact with susceptible cells, and how producer cells are protected against the antimicrobial properties of the microcins. For microcin PDI (MccPDI), we report that the spectrum of activity likely includes most E. coli strains due to a conserved binding motif found on an outer membrane protein. Shigella has this motif as well and is susceptible to MccPDI killing via damage to the bacterial membrane. Receptor specificity suggests that these proteins could be used without causing large-scale disruptions to a microbiota, but this also increases the likelihood that resistance can evolve via random mutations. As with conventional antibiotics, good stewardship will be needed to preserve the efficacy of microcins should they be deployed for clinical use.

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The critical role of DNA in the equilibrium between OmpR and phosphorylated OmpR mediated by EnvZ in Escherichiacoli

Cited by 9 publications

References 28 publications

Transcriptional Responses of Leptospira interrogans to Host Innate Immunity: Significant Changes in Metabolism, Oxygen Tolerance, and Outer Membrane

Transcriptional Responses of Leptospira interrogans to Host Innate Immunity: Significant Changes in Metabolism, Oxygen Tolerance, and Outer Membrane

Surface Plasmon Resonance Imaging of Transcription Factor Proteins: Interactions of Bacterial Response Regulators with DNA Arrays on Gold Films

Microcin PDI Inhibits Antibiotic-Resistant Strains of Escherichia coli and Shigella through a Mechanism of Membrane Disruption and Protection by Homotrimer Self-Immunity

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