Deletion of the Aspergillus fumigatus lysine biosynthesis gene lysF encoding homoaconitase leads to attenuated virulence in a low-dose mouse infection model of invasive aspergillosis.
Aspergillus fumigatus is an important pathogen of the immunocompromised host, causing pneumonia and invasive disseminated disease with high mortality. In order to determine the importance of lysine biosynthesis for growth and pathogenicity, the A. fumigatus lysF gene, encoding a homologue of the A. nidulans homoaconitase LysF, was cloned and characterized. Cosmid cosGTM encoding lysF complemented a lysF mutant of Aspergillus nidulans. A. fumigatus lysF was deleted, resulting in a lysine-auxotroph. This phenotype was complemented to the wild-type by supplementation of the medium with both L-lysine and alpha-aminoadipic acid, or transformation using cosmid cosGTM. To study the virulence of the lysF deletion mutant of A. fumigatus, a low-dose intranasal mouse infection model of invasive aspergillosis was optimized for immunosuppressed BALB/c mice, allowing the application of an infection dose as low as 5 x 10(3) conidia per mouse. In this murine model, the Delta lysF mutant was avirulent, suggesting that lysine biosynthesis, or at least a functional homoaconitase, is important for survival of A. fumigatus in vivo and a potential target for antifungal drugs.
Liebmann
Burghard
B
Institut für Mikrobiologie, Universität Hannover, Schneiderberg 50, 30167, Hannover, Germany.
Mühleisen
Thomas W
TW
Müller
Meike
M
Hecht
Matthias
M
Weidner
Gerhard
G
Braun
Armin
A
Brock
Matthias
M
Brakhage
Axel A
AA
D000818:Animals; D001228:Aspergillosis / Q000382:microbiology; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D001483:Base Sequence; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D004195:Disease Models, Animal; D017353:Gene Deletion; D005800:Genes, Fungal; D006836:Hydro-Lyases / Q000235:genetics*; D008172:Lung Diseases, Fungal / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D014774:Virulence / Q000235:genetics / Q000502:physiology
D004271:DNA, Fungal; D006836:Hydro-Lyases; C107855:homoaconitate hydratase