Characterization of common virulence plasmids in Yersinia species and their role in the expression of outer membrane proteins

Abstract

The virulence plasmids pYV019, pYV8081 and pIB1 from Y. pestis, Y. enterocolitica and Y. pseudotuberculosis, respectively, were characterized by restriction endonuclease analysis. The 3 plasmids exhibited a region of common DNA previously shown to encode determinants which confer Ca2+ dependence. The plasmids from Y. pestis and Y. pseudotuberculosis were similar throughout their genomes. A region of the plasmid from Y. enterocolitica which contained an origin of replication differed from the other 2 plasmids as determined by DNA homology and replication properties. Plasmid-associated outer membrane proteins from all 3 spp. of Yersinia were characterized by polyacryl-amide gel electrophoresis. There were no differences in the outer membrane protein profiles between plasmid-containing and homogenic strains lacking the plasmid after growth at 28.degree. C. After growth at 37.degree. C, Y. enterocolitica and Y. pseudotuberculosis showed at least 4 major plasmid-associated outer membrane proteins. Y. pestis did not show any discernible changes after growth at 37.degree. C. It was shown by using Escherichia coli minicell analysis that the plasmid DNA from all 3 spp. of Yersinia contained the coding capacity for production of the novel outer membrane proteins.