The virulence plasmid of Yersinia, an antihost genome

The Yersinia outer membrane protein (YOP) and the type III virulence system of the pathogenic bacteria were described. This system involved the transfer of bacterial proteins by the extracellular bacteria to the cytosol of the eukaryotic cell. The three species of Yersinia considered as pathogens in mammals are Y. pestis, Y. pseudotuberculosis and Y. enterocolitica. Genetic analysis revealed that majority of Yop proteins were necessary for virulence and cytotoxicity activity. The Yops were classified as secreted proteins. The pYV plasmid and the ysc genes encoded the Yop secretion apparatus.