Role of the Nucleoid-Associated Protein H-NS in the Synthesis of Virulence Factors in the Phytopathogenic Bacterium <i>Erwinia chrysanthemi</i>

Nasser, William; Faelen, Michel; Hugouvieux‐Cotte‐Pattat, Nicole; Reverchon, Sylvie

doi:10.1094/mpmi.2001.14.1.10

Cited by 47 publications

(43 citation statements)

References 58 publications

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“…To study the expression of the ousB operon, ousV was fused to the uidA reporter gene in the mutant strain A3779 (49), and the induction of ousB was monitored by measuring the level of GUS activity. The transcription of ousB was at basal level when cells were grown at low osmolality ( Fig.…”

Section: Resultsmentioning

confidence: 99%

OusB, a Broad-Specificity ABC-Type Transporter fromErwinia chrysanthemi, Mediates Uptake of Glycine Betaine and Choline with a High Affinity

Choquet

Jehan

Pissavin

et al. 2005

Appl Environ Microbiol

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The ability of Erwinia chrysanthemi to cope with environments of elevated osmolality is due in part to the transport and accumulation of osmoprotectants. In this study we have identified a high-affinity glycine betaine and choline transport system in E. chrysanthemi. By using a pool of Tn5-B21 ousA mutants, we isolated a mutant that could grow in the presence of a toxic analogue of glycine betaine (benzyl-glycine betaine) at high osmolalities. This mutant was impaired in its ability to transport all effective osmoprotectants in E. chrysanthemi. The DNA sequence of the regions flanking the transposon insertion site revealed three chromosomal genes (ousVWX) that encode components of an ABC-type transporter (OusB): OusV (ATPase), OusW (permease), and OusX (periplasmic binding protein). The OusB components showed a significant degree of sequence identity to components of ProU from Salmonella enterica serovar Typhimurium and Escherichia coli. OusB was found to restore the uptake of glycine betaine and choline through functional complementation of an E. coli mutant defective in both ProU and ProP osmoprotectant uptake systems. Competition experiments demonstrated that choline, dimethylsulfoniacetate, dimethylsulfoniopropionate, and ectoine were effective competitors for OusB-mediated betaine transport but that carnitine, pipecolate, and proline were not effective. In addition, the analysis of single and double mutants showed that OusA and OusB were the only osmoprotectant transporters operating in E. chrysanthemi.

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Section: Resultsmentioning

confidence: 99%

OusB, a Broad-Specificity ABC-Type Transporter fromErwinia chrysanthemi, Mediates Uptake of Glycine Betaine and Choline with a High Affinity

Choquet

Jehan

Pissavin

et al. 2005

Appl Environ Microbiol

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“…Since there is no evidence that H-NS can act as a transcriptional activator, it has been postulated that H-NS may play an indirect role (reviewed in reference 13). For the Erwinia chrysanthemi pectate lyase synthesis genes (40,41) and E. coli flagellar synthesis genes (2, 3), it has been found that H-NS exerts it control, not on these promoters directly, but at the promoters of transcriptional repressors that act upon these target genes. Similarly, it may be that H-NS disrupts the regulation of cirA, fes, srlE, and hisJ through indirect effects.…”

Section: Vol 189 2007mentioning

confidence: 99%

Human Body Temperature (37°C) Increases the Expression of Iron, Carbohydrate, and Amino Acid Utilization Genes in Escherichia coli K-12

Malhowski

Young

2007

J Bacteriol

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Using DNA microarrays, we identified 126 genes in Escherichia coli K-12 whose expression is increased at human body temperature (37°C) compared to growth at 23°C. Genes involved in the uptake and utilization of amino acids, carbohydrates, and iron dominated the list, supporting a model in which temperature serves as a host cue to increase expression of bacterial genes needed for growth. Using quantitative real-time PCR, we investigated the thermoregulatory response for representative genes in each of these three categories (hisJ, cysP, srlE, garP, fes, and cirA), along with the fimbrial gene papB. Increased expression at 37°C compared to 23°C was retained in both exponential and stationary phases for all of the genes and in most of the various media tested, supporting the relative importance of this cue in adapting to changing environments. Because iron acquisition is important for both growth and virulence, we analyzed the regulation of the iron utilization genes cirA and fes and found that growth in iron-depleted medium abrogated the thermoregulatory effect, with high-level expression at both temperatures, contrasting with papB thermoregulation, which was not greatly altered by limiting iron levels. A positive role for the environmental regulator H-NS was found for fes, cirA, hisJ, and srlE transcription, whereas it had a primarily negative effect on cysP and garP expression. Together, these studies indicate that temperature is a broadly used cue for regulating gene expression in E. coli and that H-NS regulates iron, carbohydrate, and amino acid utilization gene expression.

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“…A Vibrio cholerae ⌬hns strain exhibited reduced motility, enhanced in vivo production of virulence factors, and lower colonization efficiency (28). In the plant pathogen Erwinia chrysanthemi, the ⌬hns mutant strain displayed a reduced virulence phenotype (29). In the Shiga toxin-producing E. coli O91:H21 strain B2F1, a mutation in hns reduced adherence to human colonic epithelial cells (30).…”

Section: Discussionmentioning

confidence: 99%

Finding Regulators Associated with the Expression of the Long Polar Fimbriae in Enteropathogenic Escherichia coli

Ross

Cieza

et al. 2015

J Bacteriol

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Enteropathogenic Escherichia coli (EPEC) is a human pathogen that requires initial adhesion to the intestine in order to cause disease. Multiple adhesion factors have been identified in E. coli strains, among them the long polar fimbriae (Lpf), a colonization factor associated with intestinal adhesion. The conditions of Lpf expression are well understood in enterohemorrhagic E. coli (EHEC); however, the expression of EPEC lpf has been found to be repressed under any in vitro condition tested. Therefore, we decided to identify those factors silencing expression of EPEC lpf. Because histone-like nucleoid structuring protein (H-NS) is a known repressor of EHEC lpf, we tested it and found that H-NS is a repressor of EPEC lpf. We also found that the adhesion of the EPEC ⌬hns strain was significantly enhanced compared to the wild-type strain. Because lpf expression was modestly increased in the hns mutant, transposon mutagenesis was performed to find a strain displaying higher lpf expression than EPEC ⌬hns. One Tn5 insertion was identified within the yhjX gene, and further in vitro characterization revealed increased lpf expression and adhesion to Caco-2 cells compared with EPEC ⌬hns. However, in a murine model of intestinal infection, the EPEC ⌬hns and EPEC ⌬hns Tn5 mutants had only a slight change in colonization pattern compared to the wild-type strain. Our data showed that EPEC Lpf is transcribed, but its role in EPEC intestinal colonization requires further analysis. IMPORTANCEData are presented demonstrating that the long polar fimbriae (lpf) operon in enteropathogenic E. coli (EPEC) is highly regulated; however, derepression occurs by mutagenizing two proteins associated with its control. The study demonstrates that the EPEC lpf operon can be expressed and, therefore, participates in the EPEC adherence phenotype. E scherichia coli bacteria are normally found in the intestines of humans and animals. Most E. coli strains rarely cause disease, except in immunocompromised hosts or in individuals whose normal gastrointestinal barrier is broken (1, 2). However, there are several E. coli strains that carry specific virulence attributes that classify them in specific pathotypes that cause distinct disease in healthy hosts (1). Two of these E. coli pathotypes, enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC), belong to the group of attaching and effacing E. coli (AEEC) strains. AEEC strains are characterized by the presence of a type III secretion system (T3SS) that injects virulence factors into the host cell, mediating the formation of the characterized histopathological attaching and effacing (A/E) lesion (1, 2). EPEC is a leading cause of human infantile diarrhea worldwide (3, 4). EHEC also causes severe human disease, including bloody diarrhea and life-threatening hemolytic uremic syndrome (HUS). Currently, EPEC is estimated to be responsible for 5 to 10% of pediatric diarrhea in developing countries (3). The Global Enteric Multicenter Study (GEMS) showed that some EPEC strains are assoc...

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Role of the Nucleoid-Associated Protein H-NS in the Synthesis of Virulence Factors in the Phytopathogenic Bacterium Erwinia chrysanthemi

Cited by 47 publications

References 58 publications

OusB, a Broad-Specificity ABC-Type Transporter fromErwinia chrysanthemi, Mediates Uptake of Glycine Betaine and Choline with a High Affinity

OusB, a Broad-Specificity ABC-Type Transporter fromErwinia chrysanthemi, Mediates Uptake of Glycine Betaine and Choline with a High Affinity

Human Body Temperature (37°C) Increases the Expression of Iron, Carbohydrate, and Amino Acid Utilization Genes in Escherichia coli K-12

Finding Regulators Associated with the Expression of the Long Polar Fimbriae in Enteropathogenic Escherichia coli

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