Isolation and identification of eight genetic loci from the intracellular pathogen 'Francisella novicida'
Date
2000
Authors
Gray, Catherine Jean
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Shuttle transposon mutagenesis of the intracellular bacterial pathogen F. novicida resulted in eight mutants which showed decreased growth in intraperitoneal murine macrophages as compared to the wildtype strain. The genetic loci flanking the transposon were isolated and characterized by DNA sequencing. Five of the eight mutant clones showed similarity to database entries at the deduced amino acid level. One of the mutants, designated CG62, was interrupted in a presumed gene encoding a protein identical to a possible virulence factor found in F. tularensis. This protein is expressed only when the bacterium is growing inside macrophages, and when it is exposed to hydrogen peroxide. The protein has been termed Fip, for Francisella intramacrophage protein. Four of the F. novicida mutants had interrupted genetic regions similar to genes for a stress response protein, a purine biosynthesis protein, alanine racemase and a protein of unknown function found in E. coli and V. cholerae, respectively. The other three mutant strains appear to have been interrupted in unknown genetic regions, which may encode novel proteins involved in virulence.