title: Mutants in the ptlA-H genes of Bordetella pertussis are deficient for pertussis toxin secretion.
abstract: The nine ptl genes (A-I) are required for efficient secretion of pertussis toxin past the outer membrane. Mutations were made in ptlA-H by filling in unique restriction sites, generating in-frame deletions, or inserting a FLAG epitope tag. The mutations were cloned into a suicide shuttle plasmid containing the ptxptl operon and introduced into the adenylate cyclase locus of the chromosome of a Bordetella pertussis strain deleted for ptx. The wild-type ptxptl operon restored pertussis toxin expression and secretion. The ptl mutant constructs also restored expression of periplasmic pertussis toxin to the ptx deletion strain but the mutants had a statistically significant decrease in secretion of pertussis toxin of between 5- to 35-fold, suggesting all of the ptl genes must be intact for efficient pertussis toxin secretion. The mutations were also introduced into the adenylate cyclase locus of a wild-type ptxptl strain, resulting in a ptl diploid strain. The PtlC, PtlD, PtlE, PtlF, PtlG and PtlH mutants exerted dominance over the wild-type allele.
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, 231 Bethesda Ave., Cincinnati, OH 45267-0524, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Craig-Mylius
authors.forename: A A
authors.initials: AA
authors.lastname: Weiss
mesh_terms: D037361:Adenylate Cyclase Toxin; D001886:Bordetella pertussis / Q000235:genetics*; D009154:Mutation; D009876:Operon; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D037361:Adenylate Cyclase Toxin; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin