Locus of the Pseudomonas aeruginosa toxin A gene

The gene for Pseudomonas aeruginosa toxin A has been mapped in the late region of the chromosome of strain PAO. Strain PAO-PR1, which produces parental levels of toxin A antigen that is enzymatically inactive and nontoxic, was used as the donor for R68.45 plasmid-mediated genetic exchange. Strain PAO-PR1 (toxA1) was mated with toxin A-producing strains, and exconjugates for selected prototrophic markers were tested for the transfer of toxA1. The toxA1 gene was located between cnu-9001 and pur-67 at approximately 85 min on the PAO chromosome.