Influence of the alternative sigma(28) factor on virulence and flagellum expression of Legionella pneumophila.
The fliA gene of Legionella pneumophila encoding the alternative sigma(28) factor was inactivated by introducing a kanamycin resistance cassette. Electron microscopy and Western blot analysis revealed that the fliA mutant strain is aflagellate and expresses no flagellin. Reporter gene assays indicated that the flaA promoter is not active in the fliA mutant strain. The fliA mutant strain multiplied less effectively in coculture with amoebae than the wild-type strain and was not able to replicate in coculture with Dictyostelium discoideum.
Heuner
Klaus
K
Institut für Molekulare Infektionsbiologie, Universität Würzburg, 97070 Würzburg, Germany. klaus.heuner@mail.uni-wuerzburg.de
Dietrich
Claudia
C
Skriwan
Carina
C
Steinert
Michael
M
Hacker
Jörg
J
D000048:Acanthamoeba / Q000382:microbiology; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D018920:Coculture Techniques; D004023:Dictyostelium / Q000382:microbiology; D056890:Eukaryota / Q000382:microbiology*; D005407:Flagella / Q000235:genetics*; D005408:Flagellin / Q000096:biosynthesis; D016952:Legionella pneumophila / Q000235:genetics / Q000472:pathogenicity*; D009154:Mutation; D012808:Sigma Factor / Q000235:genetics*
D001426:Bacterial Proteins; C064971:FliA protein, Bacteria; D012808:Sigma Factor; D005408:Flagellin