DNA Adenine Methylase Is Essential for Viability and Plays a Role in the Pathogenesis of Yersinia pseudotuberculosisandVibrio cholerae

ABSTRACTSalmonellastrains that lack or overproduce DNA adenine methylase (Dam) elicit a protective immune response to differentSalmonellaspecies. To generate vaccines against other bacterial pathogens, the damgenes of Yersinia pseudotuberculosisand Vibrio choleraewere disrupted but found to be essential for viability. Overproduction of Dam significantly attenuated the virulence of these two pathogens, leading to, in Yersinia, the ectopic secretion of virulence proteins (Yersiniaouter proteins) and a fully protective immune response in vaccinated hosts. Dysregulation of Dam activity may provide a means for the development of vaccines against varied bacterial pathogens.