Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis

Carbonetti, Nicholas H.; Fuchs, Thilo M.; Patamawenu, A A; Irish, Teresa J.; Deppisch, Heike; Gross, Roy

doi:10.1128/jb.176.23.7267-7273.1994

Cited by 38 publications

(38 citation statements)

References 41 publications

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“…Mutations affecting only Ptx or Cya expression mapped in or near ptx or cya, respectively, while mutations affecting Ptx and Cya expression mapped at or near bvg or rpoA (18). Mutations mapping to the rpoA locus of B. pertussis which have a Ptx-Cya-Fha' phenotype have recently been described (6,7,31). This paper describes the further characterization of two mutations which were mapped to the bvg locus.…”

Section: Discussionmentioning

confidence: 98%

Mutations in the bvgA gene of Bordetella pertussis that differentially affect regulation of virulence determinants

Stibitz

1994

J Bacteriol

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By using chemical mutagenesis and genetic mapping, a search was undertaken for previously undescribed genes which may be involved in different regulatory mechanisms governing different virulence factors of Bordetella pertussis. Previous studies have shown that the fha locus encoding filamentous hemagglutinin is regulated directly by the bvgAS two component system, while regulation of ptx encoding pertussis toxin is less direct or occurs by a different mechanism. With a strain containing gene fusions to each of these regulated loci, screening was done for mutations which were defective for ptx expression but maintained normal or nearly normal levels of fha expression. Two mutations which had such a phenotype and were also deficient in adenylate cyclase toxin/hemolysin expression were found and characterized more fully. Both were found to affect residues in the C-terminal portion of the BvgA response regulator protein, a domain which shares sequence similarity with a family of regulatory proteins including FixJ, UhpA, MalT, RcsA, RcsB, and LuxR. The residues affected are within a region which, by extension from studies on the LuxR protein, may be involved in transcriptional activation.

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Section: Discussionmentioning

confidence: 98%

Mutations in the bvgA gene of Bordetella pertussis that differentially affect regulation of virulence determinants

Stibitz

1994

J Bacteriol

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“…This has led to speculation that the bvg virulence control system may have a downstream activator that participates in ptxA expression, much like the ToxRS-ToxT regulatory system of Vibrio cholerae (13). Several mutations conferring an Fha ϩ Cya Ϫ Ptx Ϫ phenotype have been isolated and mapped (9,48). These mutations are not located in a putative downstream transcriptional activator but are instead found upstream of the translational start site of rpoA or in the C terminus of BvgA, invoking a model in which BvgA interacts with RpoA at the ptxA promoter.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, initial reports indicated that bvgAS was not sufficient for activation of ptxA and cya transcriptional fusions in E. coli (17,33). These results suggested that an intermediate factor was required for expression of pertussis toxin and adenylate cyclase; however, such a factor has not yet been described (9,31,48). …”

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confidence: 97%

BvgAS is sufficient for activation of the Bordetella pertussis ptx locus in Escherichia coli

Uhl

Miller

1995

J Bacteriol

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BvgA and BvgS, which regulate virulence gene expression in Bordetella pertussis, are members of the two-component signal transduction family. The effects of growth conditions on the ability of BvgAS to activate transcription of fhaB (encoding filamentous hemagglutinin) and ptxA (encoding the S1 subunit of pertussis toxin) were assessed in Escherichia coli by using chromosomal fhaB-lacZYA and ptxA-lacZYA fusions. Although it had previously been reported that a ptxA-lacZYA transcriptional fusion was not activated by bvgAS in E. coli (J. F. Miller, C. R. Roy, and S. Falkow, J. Bacteriol. 171:6345-6348, 1989), we now present evidence that ptxA is activated by bvgAS in E. coli in a manner that is highly dependent on the growth conditions. Higher levels of ␤-galactosidase were produced by ptxA-lacZYA in the presence of bvgAS during growth in Stainer-Scholte medium or M9 minimal salts medium with glucose than in Luria-Bertani medium. In contrast, the level of fhaB-lacZYA expression was high during growth in all media. Addition of modulating stimuli which inhibit BvgAS function eliminated expression of ptxA-lacZYA. Levels of ␤-galactosidase expressed from the ptx-lacZYA fusion correlated with growth rate and with the final optical density at 600 nm, suggesting that the lower growth rate in M9-glucose and Stainer-Scholte media was responsible for greater accumulation of ␤-galactosidase than was seen in Luria-Bertani medium. Overproduction of BvgA was not sufficient for activation of ptxA expression but was sufficient for fhaB expression. However, overproduction of a constitutive BvgA allele (bvgA-C1) or overproduction of BvgA in the presence of BvgS was able to activate ptxA. Our results demonstrate Bvg-dependent activation of a ptxA-lacZYA fusion in E. coli and indicate that bvg is the only Bordetella locus required for ptxA activation in this heterologous system. Bordetella pertussis, the causative agent of whooping cough, synthesizes toxins and adhesins which appear to aid the bacterium in colonization and multiplication (15,23,28,38,56,59). Expression of toxins (pertussis toxin, adenylate cyclasehemolysin, and dermonecrotic toxin) and adhesins (filamentous hemagglutinin, fimbriae, and pertactin) is positively regulated by the products of the bvg operon (11,57,59). In contrast to the multiple loci activated by bvg, vrg genes of B. pertussis (5,6,25), siderophore production in some Bordetella bronchiseptica strains (14), and motility genes of B. bronchiseptica (1-3) are repressed by bvg.Sequence analysis and in vitro studies have indicated that BvgA and BvgS are members of the two-component family of signal transduction proteins. BvgS is a 135-kDa sensor protein localized to the cytoplasmic membrane, and BvgA is a 23-kDa cytoplasmic response regulator (4, 7, 37, 49, 50-53). The signals sensed by BvgAS in vivo are not known, but BvgAS can be inactivated in vitro by growth at a low temperature or by addition of sulfate anion or nicotinic acid to the culture medium. This reversible inactivation of BvgAS is known as phenot...

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“…The resulting BamHI fragment was then cloned into the allelic exchange vector pSS1129. The resulting construct, pSS1129-DcspB, was transferred by conjugation into B. bronchiseptica, and selection for double-crossover events was carried out as described elsewhere (Carbonetti et al, 1994;Stibitz & Yang, 1991). The resulting cspB deletion mutant was termed BB7865DcspB.…”

Section: Methodsmentioning

confidence: 99%

Identification and regulation of cold-inducible factors of Bordetella bronchiseptica

et al. 2005

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The expression of bacterial cold-shock proteins (CSPs) is highly induced in response to cold shock, and some CSPs are essential for cells to resume growth at low temperature. Bordetella bronchiseptica encodes five CSPs (named CspA to CspE) with significant amino acid homology to CspA of Escherichia coli. In contrast to E. coli, the insertional knock-out of a single csp gene (cspB) strongly affected growth of B. bronchiseptica independent of temperature. In the case of three of the csp genes (cspA, cspB, cspC) more than one specific transcript could be detected. The net amount of cspA, cspB and cspC transcripts increased strongly after cold shock, while no such effect could be observed for cspD and cspE. The exposure to other stress conditions, including translation inhibitors, heat shock, osmotic stress and nutrient deprivation in the stationary phase, indicated that the csp genes are also responsive to these conditions. The coding regions of all of the cold-shock genes are preceded by a long non-translated upstream region (59-UTR). In the case of the cspB gene, a deletion of parts of this region led to a significant reduction of translation of the resulting truncated transcript, indicating a role of the 59-UTR in translational control. The cold-shock stimulon was investigated by 2D-PAGE and mass spectrometric characterization, leading to the identification of additional cold-inducible proteins (CIPs). Interestingly, two cold-shock genes (cspC and cspD) were found to be under the negative control of the BvgAS system, the main transcriptional regulator of Bordetella virulence genes. Moreover, a negative effect of slight overexpression of CspB, but not of the other CSPs, on the transcription of the adenylate cyclase toxin CyaA of Bordetella pertussis was observed, suggesting cross-talk between the CSP-mediated stress response stimulon and the Bordetella virulence regulon.

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Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis

Cited by 38 publications

References 41 publications

Mutations in the bvgA gene of Bordetella pertussis that differentially affect regulation of virulence determinants

Mutations in the bvgA gene of Bordetella pertussis that differentially affect regulation of virulence determinants

BvgAS is sufficient for activation of the Bordetella pertussis ptx locus in Escherichia coli

Identification and regulation of cold-inducible factors of Bordetella bronchiseptica

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