Nucleotide sequence of a plasmid-encoded hemolysin determinant and its comparison with a corresponding chromosomal hemolysin sequence

Hess, Jürgen

doi:10.1016/0378-1097(86)90261-2

Cited by 72 publications

(103 citation statements)

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“…In order to determine whether any homology between the species exists, the DNA sequence of the region upstream from cyaA from previously published reports (11) and new data generated in this laboratory were analyzed. Our data allowed the identification of an open reading frame oriented oppositely from the cyaA gene with striking homology to the E. coli hlyC gene (8,14) (Fig. 3).…”

Section: Resultsmentioning

confidence: 84%

Bordetella pertussis adenylate cyclase toxin and hemolytic activities require a second gene, cyaC, for activation

et al. 1991

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In these studies, the Bordetella pertussis adenylate cyclase toxin-hemolysin homology to the Escherichia coli hemolysin is extended with the finding of cyaC, a homolog to the E. coli hlyC gene, which is required for the production of a functional hemolysin molecule in E. coli. Mutations produced in the chromosome of B. pertussis upstream from the structural gene for the adenylate cyclase toxin revealed a region which was necessary for toxin and hemolytic activities of the molecule. These mutants produced the 216-kDa adenylate cyclase toxin as determined by Western blot (immunoblot) analysis. The adenylate cyclase enzymatic activities of these mutants were equivalent to that of wild type, but toxin activities were <1% of that of wild type, and the mutants were nonhemolytic on blood agar plates and in in vitro assays. The upstream region restored hemolytic activity when returned in trans to the mutant strains. This genetic complementation defined a gene which acts in trans to activate the adenylate cyclase toxin posttranslationally. Sequence analysis of the upstream region defined an open reading frame with homology to the E. coli hlyC gene. In contrast to E. coli, this open reading frame is oriented oppositely from the adenylate cyclase toxin structural gene.

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Section: Resultsmentioning

confidence: 84%

Bordetella pertussis adenylate cyclase toxin and hemolytic activities require a second gene, cyaC, for activation

et al. 1991

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“…The a-haemolysin speci®c PCR primers (Hess et al, 1986) were used to produce the DNA probe for hly-speci®c hybridization experiments. Both heat-stable enterotoxin (sta and stb) probes were prepared by speci®c PCR reactions (Alexa et al, 1997).…”

Section: Dna Probes and Dna Hybridizationmentioning

confidence: 99%

Replicon typing of F18 fimbriae encoding plasmids of enterotoxigenic and verotoxigenic Escherichia coli strains from porcine postweaning diarrhoea and oedema disease

Fekete

Gérardin

Jacquemin

et al. 2002

Veterinary Microbiology

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The presence of ®mbrial adhesin F18 is frequently found in enterotoxigenic Escherichia coli (ETEC) and verotoxigenic E. coli (VTEC) strains responsible for diarrhoea and oedema disease of weaned pigs. The F18 adhesin occurs in two antigenic variants: F18ab is characteristic of VTEC while F18ac is more typical for ETEC. F18 encoding plasmids of 17 phenotypically characterized porcine E. coli isolates (10 ETEC, 6 VTEC and 1 ETEC/VTEC) were tested with a DNA probe for F18 ®mbrial adhesin and with replicon probes for the RepFIa, RepFIb and for the RepFIc family of basic replicons. In all the cases, the F18 probe hybridized to only one plasmid band of size higher than 42 MDa. All F18 plasmids were determined to be unireplicon plasmids belonging to the RepFIc replicon family of the F incompatibility complex. There was no difference between F18ac plasmids of ETEC and F18ab plasmids of VTEC strains in terms of replicon type or subtype. However, the size of F18ab plasmids of the VTEC strains varied between 42 and 98 MDa, in contrast to F18ac plasmids of ETEC strains (constantly approximately 98 MDa). #

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“…Transcription of the hly operon produces a major 4-kb hlyCA transcript and a minor 8-kb hlyCABD transcript (31). The two transcripts initiate at the same promoter, located upstream of the hlyC gene (12,31). The minor transcript is thought to be produced by readthrough, or antitermination, at a Rho-independent transcriptional terminator located between hlyA and hlyB (15).…”

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confidence: 99%

hlyM, a transcriptional silencer downstream of the promoter in the hly operon of Escherichia coli

et al. 1995

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Transcription of the hly operon of transmissible plasmids in Escherichia coli is subject to a tight regulation which also involves various chromosomal genes, such as hha. We have identified a 200-bp region within the hlyC gene, designated hlyM, which modulates hemolysin expression. The deletion of hlyM increased the activity of hly::galK fusion 20-fold. hlyM does not contain any internal promoter, nor is it capable of acting in trans. Our data suggest that the chromosomal Hha protein interacts with hlyM in order to silence the hly promoter. In addition, hlyR, a positive activator of hemolysin expression, seems to suppress the modulatory effect dictated by the Hha protein on the hlyM region.Synthesis and secretion of hemolysin are determined by the hly operon located either on the chromosome or on conjugative plasmids (10). Transcription of the hly operon produces a major 4-kb hlyCA transcript and a minor 8-kb hlyCABD transcript (31). The two transcripts initiate at the same promoter, located upstream of the hlyC gene (12, 31). The minor transcript is thought to be produced by readthrough, or antitermination, at a Rho-independent transcriptional terminator located between hlyA and hlyB (15). Similar patterns of expression have been reported for the leukotoxins of Pasteurella (27) and Actinobacillus (26) species.In the case of the plasmid hly operons, a 600-bp sequence (hlyR) located 1.5 kb upstream of hlyC is known to increase hemolysin expression (29). The primary mechanism by which hlyR exerts its action has been proposed to be antitermination at the hlyA-hlyB transcriptional terminator (15,16).Hemolysin expression is a rather complex process in which chromosomal genes are involved as well. Three of them, tolC (30), hha (9, 21), and more recently sfrB (1), have been identified. The hha gene was identified during analysis of hemolysin expression in cells harboring the hemolytic recombinant plasmid pANN202-312, which contains the cluster hlyCABD from

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Nucleotide sequence of a plasmid-encoded hemolysin determinant and its comparison with a corresponding chromosomal hemolysin sequence

Cited by 72 publications

References 0 publications

Bordetella pertussis adenylate cyclase toxin and hemolytic activities require a second gene, cyaC, for activation

Bordetella pertussis adenylate cyclase toxin and hemolytic activities require a second gene, cyaC, for activation

Replicon typing of F18 fimbriae encoding plasmids of enterotoxigenic and verotoxigenic Escherichia coli strains from porcine postweaning diarrhoea and oedema disease

hlyM, a transcriptional silencer downstream of the promoter in the hly operon of Escherichia coli

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