title: Alteration of DNA adenine methylase (Dam) activity in Pasteurella multocida causes increased spontaneous mutation frequency and attenuation in mice.
abstract: Pasteurella multocida is one of the primary bacterial pathogens associated with bovine respiratory disease (BRD) complex. Relatively few virulence factors of P. multocida have been characterized, and there is a need for improved vaccines for prevention of BRD. In other Gram-negative species, DNA adenine methylase (Dam) regulates the expression of virulence genes, and appropriate expression of Dam is required for virulence. In this study, the authors cloned and sequenced the P. multocida A1 dam gene and demonstrated that it is able to restore Dam function in an Escherichia coli dam mutant. When P. multocida dam was placed under the control of a constitutively expressed promoter on a plasmid, it caused an increased spontaneous mutation rate in P. multocida. In addition, the plasmid-mediated alteration of Dam production in P. multocida caused it to be highly attenuated in mice. These findings indicate that appropriate expression of Dam is required for virulence of P. multocida, which is believed to be the first report that Dam is required for virulence of a species in the Pasteurellaceae. Therefore, Dam may function as a virulence gene regulator in the Pasteurellaceae, similar to previously reported findings from other Gram-negative species.
authors.affiliation: Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Paulsen
authors.affiliation: Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Scruggs
authors.affiliation: Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Banes
authors.affiliation: Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA.
authors.forename: Brenda Y
authors.initials: BY
authors.lastname: Reeks
authors.affiliation: Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Lawrence
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005260:Female; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009154:Mutation; D010326:Pasteurella Infections / Q000209:etiology; D016979:Pasteurella multocida / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D010641:Phenotype; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000378:metabolism*; D014774:Virulence / Q000235:genetics / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)