Comparison of the PhoPQ regulon in Escherichia coli and Salmonella typhimurium

P Monsieurs, S De Keersmaecker, WW Navarre, MW Bader, F De Smet, M McClelland, FC Fang, B De Moor, J Vanderleyden, K Marchal

    Research output: Contribution to journalA1: Web of Science-article

    Abstract

    The PhoPQ two-component system acts a transcriptional regulator that responds to Mg2+ starvation both in Escherichia coli and Salmonella typhimurium (Garcia et al. 1996; Kato et al. 1999). By monitoring the availability of extracellular Mg2+, this two-component system allows S. typhimurium to sense the transition from an extracellular environment to a subcellular location. Concomitantly with this transition, a set of virulence factors essential for survival in the intracellular environment is activated by the PhoPQ system (Groisman et al. 1989; Miller et al. 1989). Compared to nonpathogenic strains, such as E. coli K12, the PhoPQ regulon in pathogens must contain target genes specifically contributing, to the virulence phenotype. To verify this hypothesis, we compared the composition of the PhoPQ regulon between E. coli and S. typhimurium using a combination of expression experiments and motif data. PhoPQ-dependent genes in both organisms were identified from PhoPQ-related microarray experiments. To distinguish between direct and indirect targets, we searched for the presence of the regulatory motif in the promoter region of the identified PhoPQ-dependent genes. This allowed us to reconstruct the direct PhoPQ-dependent regulons in E. coli K12 and S. typhimurium LT2. Comparison of both regulons revealed a very limited overlap of PhoPQ-dependent genes between both organisms. These results suggest that the PhoPQ system has acquired a specialized function during evolution in each of these closely related species that allows adaptation to the specificities of their lifestyles (e.g., pathogenesis in S. typhimurium).

    Original languageEnglish
    JournalGenome Biology and Evolution
    Volume60
    Issue number4
    Pages (from-to)462-474
    Number of pages13
    ISSN0022-2844
    DOIs
    Publication statusPublished - Apr-2005

    Keywords

    • PhoPQ regulon
    • Escherichia coli
    • Salmonella typhimirium
    • genome evolution
    • comparative genomics
    • MOLECULAR-GENETIC-ANALYSIS
    • ANTIMICROBIAL PEPTIDES
    • 2-COMPONENT SYSTEM
    • VIRULENCE GENE
    • TOLERANCE RESPONSE
    • REGULATED GENES
    • RESISTANCE
    • ENTERICA
    • LOCUS
    • EXPRESSION

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