title: Regulation of exotoxin A synthesis in Pseudomonas aeruginosa: characterization of toxA-lacZ fusions in wild-type and mutant strains.
abstract: A mobilizable plasmid which carries the promoter for the exotoxin A (ETA) structural gene fused to lacZ was integrated into the chromosome of wild-type and mutant strains of Pseudomonas aeruginosa at the toxA locus by homologous recombination. beta-galactosidase synthesis in the strains (cointegrates) carrying the toxA-lacZ fusions was regulated like ETA synthesis is in P. aeruginosa. Two multicopy plasmids carrying a positive regulatory gene designated toxR were constructed which are identical except with respect to the orientation of toxR to the lacZ promoter on the plasmid. These plasmids were then introduced into P. aeruginosa cointegrate strains. When toxR was using its own promoter, synthesis of beta-galactosidase in the cointegrate strains was increased but the pattern of iron regulation was not altered. In contrast, when the lacZ promoter was directing synthesis of the toxR product in the cointegrate strains, iron regulation of beta-galactosidase and ETA synthesis were abolished.
authors.affiliation: Department of Microbiology and Immunology, University of Colorado, School of Medicine, Denver 80262.
authors.forename: M L
authors.initials: ML
authors.lastname: Vasil
authors.forename: C C
authors.initials: CC
authors.lastname: Grant
authors.forename: R W
authors.initials: RW
authors.lastname: Prince
mesh_terms: D036002:ADP Ribose Transferases; D001427:Bacterial Toxins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D005098:Exotoxins / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005809:Genes, Regulator; D015151:Immunoblotting; D007501:Iron / Q000502:physiology; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D015183:Restriction Mapping; D037521:Virulence Factors; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics; D000097668:Pseudomonas aeruginosa Exotoxin A
chemical_list: D036002:ADP Ribose Transferases; D001427:Bacterial Toxins; D005098:Exotoxins; D007501:Iron; D011993:Recombinant Fusion Proteins; D037521:Virulence Factors; D001616:beta-Galactosidase; D000097668:Pseudomonas aeruginosa Exotoxin A