Multicopy icsA is able to suppress the virulence defect caused by the wzz(SF) mutation in Shigella flexneri.
The lipopolysaccharides (LPS) of Shigella flexneri are important for virulence and their O antigen (Oag) polysaccharide chains affect IcsA (VirG)-mediated actin-based motility (ABM) within mammalian cells. S. flexneri 2a 2457T has smooth LPS whose Oag chains have two modal lengths (short (S)-type and very long (VL)-type), and has IcsA predominantly located at one pole on its cell surface. A S. flexneri 2457T wzz(SF) mutant (RMA696) has VL-type Oag but not S-type Oag chains, less IcsA detectable by immunofluorescence on its cell surface, reduced virulence and defective ABM. Introduction of a plasmid encoding IcsA into S. flexneri wzz(SF) showed that multicopy icsA could suppress the virulence defects (Sereny reaction, HeLa cell monolayer plaquing, and F-actin comet tail formation) caused by the wzz(SF) mutation suggesting that the VL-type Oag chains were masking IcsA and limiting the amount available to initiate ABM.
Morona
Renato
R
School of Molecular and Biomedical Science, University of Adelaide, SA, Australia. renato.morona@adelaide.edu.au
Van Den Bosch
Luisa
L
D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D019081:O Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012763:Shigella flexneri / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology*; D014774:Virulence / Q000235:genetics*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D008070:Lipopolysaccharides; D019081:O Antigens; D014157:Transcription Factors; C058483:virG protein, Shigella flexneri; C075969:rol protein, Bacteria