The long‐term cytoskeletal rearrangement induced by rabbit enteropathogenic <i>Escherichia coli</i> is Esp dependent but intimin independent

Nougayrède, Jean-Philippe; Marchès, Olivier; Boury, Michèle; Mainil, Jacques; Charlier, G.; Pohl, P.; Rycke, Jean de; Milon, A.; Oswald, Éric

doi:10.1046/j.1365-2958.1999.01138.x

Cited by 28 publications

(30 citation statements)

References 60 publications

(89 reference statements)

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“…Taken together, the data from this and previous studies indicate that the presence of the LEE PAI in rabbit-specific aEPEC strain E22 is necessary but not sufficient for bacterial virulence (19,24,(66)(67)(68). Like other A/E pathogens, such as tEPEC and C. rodentium, E22 needs to produce a series of non-LEE-encoded virulence factors for full virulence (16,(69)(70)(71).…”

Section: Discussionsupporting

confidence: 50%

Control of Bacterial Virulence by the RalR Regulator of the Rabbit-Specific Enteropathogenic Escherichia coli Strain E22

et al. 2013

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dAtypical enteropathogenic Escherichia coli (aEPEC) causes endemic diarrhea, diarrheal outbreaks, and persistent diarrhea in humans, but the mechanism by which aEPEC causes disease is incompletely understood. Virulence regulators and their associated regulons, which often include adhesins, play key roles in the expression of virulence factors in enteric pathogenic bacteria. In this study we identified a transcriptional regulator, RalR, in the rabbit-specific aEPEC strain, E22 (O103:H2) and examined its involvement in the regulation of virulence. Microarray analysis and quantitative real-time reverse transcription-PCR demonstrated that RalR enhances the expression of a number of genes encoding virulence-associated factors, including the Ral fimbria, the Aap dispersin, and its associated transport system, and downregulates several housekeeping genes, including fliC. These observations were confirmed by proteomic analysis of secreted and heat-extracted surface-associated proteins and by adherence and motility assays. To investigate the mechanism of RalR-mediated activation, we focused on its most highly upregulated target operons, ralCDEFGHI and aap. By using primer extension, electrophoretic mobility shift assay, and mutational analysis, we identified the promoter and operator sequences for these two operons. By employing promoter-lacZ reporter systems, we demonstrated that RalR activates the expression of its target genes by binding to one or more 8-bp palindromic sequences (with the consensus of TGTGCACA) located immediately upstream of the promoter core regions. Importantly, we also demonstrated that RalR is essential for virulence since infection of rabbits with E22 carrying a knockout mutation in the ralR gene completely abolished its ability to cause disease. Enteropathogenic Escherichia coli (EPEC) is among the most important diarrheal pathogens infecting children and is also a major cause of persistent diarrhea and diarrhea-associated mortality (1, 2). The hallmark of EPEC pathogenicity is colonization of the intestine accompanied by the formation of characteristic "attaching-and-effacing" (A/E) lesions on the surface of intestinal epithelial cells (3,4). A 35-kb chromosomal pathogenicity island, termed the locus of enterocyte effacement (LEE), encodes the genetic determinants required for A/E lesion formation (5-8).EPEC can be further categorized into two subgroups, typical EPEC (tEPEC) and atypical EPEC (aEPEC) (9), which differ from each other in terms of their genetic characteristics, serotypes, and virulence factors (10,11). By definition, all EPEC strains carry the LEE, but tEPEC strains also carry an EPEC adherence factor plasmid (pEAF), which encodes a type IV-like bundle-forming pilus (Bfp) that facilitates the adherence of tEPEC cells to the intestinal mucosa and allows them to form microcolonies on epithelial cells in vitro and in vivo (11). Apart from Bfp, pEAF also encodes two transcriptional activators, PerA and PerC. The former activates transcription of bfpA (the gene for the major structur...

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Section: Discussionsupporting

confidence: 50%

Control of Bacterial Virulence by the RalR Regulator of the Rabbit-Specific Enteropathogenic Escherichia coli Strain E22

et al. 2013

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“…E22 ⌬cif::FRT is a cif deletion mutant (26) obtained according to the procedure described by Datsenko and Wanner (6). E22 espB::Kan and E22 escN::Kan are E22 mutants in which the espB and escN genes are interrupted by a kanamycin resistance gene (26,34). E22 ⌬cesT::Kan is a cesT deletion mutant obtained according to the procedure described by Datsenko and Wanner (6).…”

Section: Methodsmentioning

confidence: 99%

“…This cytostatic effect is not functionally related to cytoskeletal rearrangement but is linked to the maintenance of the cyclin-dependent kinase Cdk1, a key effector driving entry into mitosis, in a premitotic tyrosine-phosphorylated state (26,33). The ability of EPEC and EHEC strains to induce both cytoskeletal alterations and to block the G 2 /M phase transition depends on a functional LEE type III secretion machinery but not on intimin or Tir (27,34). The mode of action of Cif is not yet elucidated, and its functional domains remain to be defined.…”

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confidence: 99%

Identification of the Secretion and Translocation Domain of the Enteropathogenic and EnterohemorrhagicEscherichia coliEffector Cif, Using TEM-1 β-Lactamase as a New Fluorescence-Based Reporter

2004

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Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) strains are human and animal pathogens that inject effector proteins into host cells via a type III secretion system (TTSS). Cif is an effector protein which induces host cell cycle arrest and reorganization of the actin cytoskeleton. Cif is encoded by a lambdoid prophage present in most of the EPEC and EHEC strains. In this study, we analyzed the domain that targets Cif to the TTSS by using a new reporter system based on a translational fusion of the effector proteins with mature TEM-1 ␤-lactamase. Translocation was detected directly in living host cells by using the fluorescent ␤-lactamase substrate CCF2/AM. We show that the first 16 amino acids (aa) of Cif were necessary and sufficient to mediate translocation into the host cells. Similarly, the first 20 aa of the effector proteins Map, EspF, and Tir, which are encoded in the same region as the TTSS, mediated secretion and translocation in a type III-dependent but chaperone-independent manner. A truncated form of Cif lacking its first 20 aa was no longer secreted and translocated, but fusion with the first 20 aa of Tir, Map, or EspF restored both secretion and translocation. In addition, the chimeric proteins were fully able to trigger host cell cycle arrest and stress fiber formation. In conclusion, our results demonstrate that Cif is composed of a C-terminal effector domain and an exchangeable N-terminal translocation signal and that the TEM-1 reporter system is a convenient tool for the study of the translocation of toxins or effector proteins into host cells.

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“…tEPEC microcolonies have been also observed on infected fully differentiated HT-29 Glc Ϫ/ϩ and T84 cells, and the formation of tEPEC microcolonies increases as the brush border develops during the cell differentiation of Caco-2 cells (467). Importantly, animal EPEC-like pathogens such as Citrobacter rodentium (468), rabbit diarrheagenic E. coli (RDEC-1) (469-477), and rabbit EPEC (REPEC) (472,(476)(477)(478)(479)(480)(481)(482)(483)(484), which express virulence factors similar those of human tEPEC, have been shown to produce identical structural and functional damage in animal intestinal barriers and in cultured, fully differentiated human intestinal cells.…”

Section: Cell Interaction Cell Entry and Intracellular Lifestylementioning

confidence: 99%

Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

Moal

Servin

2013

Microbiol Mol Biol Rev

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SUMMARY Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses.

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The long‐term cytoskeletal rearrangement induced by rabbit enteropathogenic Escherichia coli is Esp dependent but intimin independent

Cited by 28 publications

References 60 publications

Control of Bacterial Virulence by the RalR Regulator of the Rabbit-Specific Enteropathogenic Escherichia coli Strain E22

Control of Bacterial Virulence by the RalR Regulator of the Rabbit-Specific Enteropathogenic Escherichia coli Strain E22

Identification of the Secretion and Translocation Domain of the Enteropathogenic and EnterohemorrhagicEscherichia coliEffector Cif, Using TEM-1 β-Lactamase as a New Fluorescence-Based Reporter

Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

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