A heptosyltransferase mutant of Pasteurella multocida produces a truncated lipopolysaccharide structure and is attenuated in virulence.
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.
Harper
Marina
M
Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
Cox
Andrew D
AD
St  Michael
Frank
F
Wilkie
Ian W
IW
Boyce
John D
JD
Adler
Ben
B
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
D008070:Lipopolysaccharides; D016695:Glycosyltransferases; C086735:heptosyltransferase