Role of crl in avian pathogenic Escherichia coli: a knockout mutation of crl does not affect hemagglutination activity, fibronectin binding, or Curli production

Provence, D L; Curtiss, rd R

doi:10.1128/iai.60.11.4460-4467.1992

Cited by 80 publications

(41 citation statements)

References 23 publications

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“…An intriguing observation that now seems relevant to Crl's function is that the requirement of crl for curli production is variable between strains (Olsen et al, 1989;Provence and Curtiss, 1992). For example, provision of crl on a multicopy plasmid restored curli production in the curlideficient strain, HB101 (Olsen et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

“…For example, provision of crl on a multicopy plasmid restored curli production in the curlideficient strain, HB101 (Olsen et al, 1989). In contrast, E. coli chi 7122 produces curli even if it lacks a functional crl gene (Provence and Curtiss, 1992). Moreover, crl, like rpoS, stimulates transcription of csgBA, which encodes the actual curlin subunit (Arnqvist et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, crl, like rpoS, stimulates transcription of csgBA, which encodes the actual curlin subunit (Arnqvist et al, 1992). Thus, functional crl is not essential for curli production in all genetic backgrounds (Provence and Curtiss, 1992) but does seem to be required in at least some strains (Olsen et al, 1989). This difference may be related to the observation that some strains carry lesions in rpoS, decreasing or abolishing its activity (Kaasen et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

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Crl stimulates RpoS activity during stationary phase

Pratt

Silhavy

1998

Molecular Microbiology

114

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RpoS, an alternative primary sigma factor, has been shown to be regulated at multiple levels, including transcription, translation and protein stability. Here, we present evidence that suggests that RpoS is regulated at yet another level by the product of the crl gene. The crl gene was first thought to encode the major curlin subunit of curli (curli are surface structures that are induced by growth into stationary phase under conditions of low osmolarity and low temperature). Later, it was determined that crl actually contributes in a positive fashion to stimulate transcription of csgBA, the true locus encoding for the major subunit of curli. RpoS is also required for normal stationary-phase induction of csgBA. We found that lesions in crl, like lesions in rpoS, cause increased transcription of ompF during stationary phase. Taken together, these observations prompted us to analyse the effects of crl on an additional RpoS-regulated phenomenon. We found that a crl null allele influences expression of RpoS-regulated genes in a fashion similar to an rpoS null allele. Genetic evidence suggests that crl and rpoS function in a single pathway and that Crl functions upstream, or in concert with, RpoS. Although the effects of Crl on RpoS-regulated genes is entirely dependent on the integrity of RpoS, the presence of a crl null allele does not decrease the level of RpoS protein. Thus, we propose that Crl stimulates the activity of the RpoS regulon by stimulating RpoS activity during stationary phase.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Crl stimulates RpoS activity during stationary phase

Pratt

Silhavy

1998

Molecular Microbiology

114

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“…Non-pathogenic as well as human, avian and animal pathogenic Escherichia coli isolates and Salmonella enterica serovars produce adhesive fimbrial structures collectively referred to as curli (Olsen et al, 1989;Collinson et al, 1991;Collinson et al, 1992;Provence and Curtiss, 1992). Morphologically, curli are thin (2-5 nm diameter), coiled, highly aggregative fibres of varying length that protrude from the bacterial surface as an amorphous matrix (Olsen et al, 1989;Bian and Normark, 1997;Collinson et al, 1997;Prigent-Combaret et al, 2000;Brown et al, 2001;Chapman et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Together with cellulose, curli form a honeycomb-like structure that enables biofilm development through bacteria-bacteria interactions and adhesion to biotic and abiotic surfaces, conferring protection against environmental foes (Gerstel and Romling, 2001;Zogaj et al, 2001;Solano et al, 2002;Jain and Chen, 2007;Jonas et al, 2007;Gualdi et al, 2008). Due to these features, curli are considered a virulence attribute in these bacteria (Provence and Curtiss, 1992;Bian et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Synergistic role of curli and cellulose in cell adherence and biofilm formation of attaching and effacing Escherichia coli and identification of Fis as a negative regulator of curli

Saldaña¹,

Xicohtencatl‐Cortes²,

Avelino³

et al. 2009

Environmental Microbiology

198

183

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Summary Curli are adhesive fimbriae of Escherichia coli and Salmonella enterica. Expression of curli (csgA) and cellulose (bcsA) is co-activated by the transcriptional activator CsgD. In this study, we investigated the contribution of curli and cellulose to the adhesive properties of enterohemorragic (EHEC) O157:H7 and enteropathogenic E. coli (EPEC) O127:H6. While single mutations in csgA, csgD, or bcsA in EPEC and EHEC had no dramatic effect on cell adherence, double csgAbcsA mutants were significantly less adherent than the single mutants or wild-type strains to human colonic HT-29 epithelial cells or to cow colon tissue in vitro. Over-expression of csgD (carried on plasmid pCP994) in a csgD mutant, but not in the single csgA or bscA mutants, led to significant increase in adherence and biofilm formation in EPEC and EHEC, suggesting that synchronized over-production of curli and cellulose enhances bacterial adherence. In line with this finding, csgD transcription was activated significantly in the presence of cultured epithelial cells as compared to growth in tissue culture medium. Analysis of the influence of virulence and global regulators in the production of curli in EPEC identified Fis (factor for inversion stimulation) as a, heretofore unrecognized, negative transcriptional regulator of csgA expression. An EPEC E2348/69Δfis produced abundant amounts of curli whereas a double fiscsgD mutant yielded no detectable curli production. Our data suggest that curli and cellulose act in concert to favor host colonization, biofilm formation, and survival in different environments.

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Curli expression of enterotoxigenicEscherichia coli

et al. 2005

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One hundred and four enterotoxin producing Escherichia coli strains of wide geographical origin were tested for the expression of curli fimbriae by transmission electronmicroscopy and by ELISA using curli-specific antibodies, as well as for the presence of curli-specific gene sequences by PCR. All isolates, irrespective of the production of the fimbriae, carried sequences specific for the structure (csgA) and for one of the regulator genes (crl) of curli expression, respectively. Curli fimbriae were detected in 56 strains (53.8 %). Thirty-six strains expressed curli only when growing at 30 degrees C, 4 isolates were weakly curliated at 37 degrees C only, while on 16 strains curli was observed at both temperatures. On isolates carrying curli at both temperatures the expression of the fimbria was significantly stronger at 30 degrees C than at 37 degrees C. Curli proficiency significantly, but not completely, correlated with the binding of the Congo Red dye. The expression of curli did not confer epithelial cell invasiveness to ETEC strains but, once expressed at 30 degrees C, it facilitated the adherence of the bacteria to plastic surfaces. Curli present in more than half of the ETEC strains and expressed preferentially at low temperatures could be a factor facilitating the environmental survival of this food- and water-borne pathogen.

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Role of crl in avian pathogenic Escherichia coli: a knockout mutation of crl does not affect hemagglutination activity, fibronectin binding, or Curli production

Cited by 80 publications

References 23 publications

Crl stimulates RpoS activity during stationary phase

Crl stimulates RpoS activity during stationary phase

Synergistic role of curli and cellulose in cell adherence and biofilm formation of attaching and effacing Escherichia coli and identification of Fis as a negative regulator of curli

Curli expression of enterotoxigenicEscherichia coli

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