title: A heptosyltransferase mutant of Pasteurella multocida produces a truncated lipopolysaccharide structure and is attenuated in virulence.
abstract: Pasteurella multocida is the causative agent of fowl cholera in birds. In a previous study using signature-tagged mutagenesis, we identified a mutant, AL251, which was attenuated for virulence in mice and in the natural chicken host. Sequence analysis indicated that AL251 had an insertional inactivation of the gene waaQ(PM), encoding a putative heptosyl transferase, required for the addition of heptose to lipopolysaccharide (LPS) (M. Harper, J. D. Boyce, I. W. Wilkie, and B. Adler, Infect. Immun. 71:5440-5446, 2003). In the present study, using mass spectrometry and nuclear magnetic resonance, we have confirmed the identity of the enzyme encoded by waaQ(PM) as a heptosyl transferase III and demonstrated that the predominant LPS glycoforms isolated from this mutant are severely truncated. Complementation experiments demonstrated that providing a functional waaQ(PM) gene in trans can restore both the LPS to its full length and growth in mice to wild-type levels. Furthermore, we have shown that mutant AL251 is unable to cause fowl cholera in chickens and that the attenuation observed is not due to increased serum sensitivity.
authors.affiliation: Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Marina
authors.initials: M
authors.lastname: Harper
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Cox
authors.forename: Frank
authors.initials: F
authors.lastname: St  Michael
authors.forename: Ian W
authors.initials: IW
authors.lastname: Wilkie
authors.forename: John D
authors.initials: JD
authors.lastname: Boyce
authors.forename: Ben
authors.initials: B
authors.lastname: Adler
mesh_terms: D000818:Animals; D002645:Chickens; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D010326:Pasteurella Infections / Q000382:microbiology / Q000662:veterinary*; D016979:Pasteurella multocida / Q000201:enzymology / Q000472:pathogenicity*; D011201:Poultry Diseases / Q000382:microbiology / Q000503:physiopathology*; D014774:Virulence
chemical_list: D008070:Lipopolysaccharides; D016695:Glycosyltransferases; C086735:heptosyltransferase