Disease relevance of ptxA

• Molecular cloning and expression of ptxA, the gene encoding the 120-kilodalton cytotoxin of Actinobacillus pleuropneumoniae serotype 2 [1].
• Weak hybridization was observed between the ptxA probe and pLKT5, which carries the lktAC genes of Pasteurella haemolytica, and between the ptxA probe and pAPH1, which carries the structural gene for type II hemolysin from A. pleuropneumoniae [1].
• 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 [2].
• 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 [2].
• 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 [2].

High impact information on ptxA

• In contrast, bvg had no effect on the pertussis toxin operon (ptxA-E) promoter in E. coli as measured by ptxA-lacZ expression [3].

References