Auto, a surface associated autolysin of Listeria monocytogenes required for entry into eukaryotic cells and virulence.
Listeria monocytogenes is an opportunistic food-borne human and animal pathogen. Several surface proteins expressed by this intracellular pathogen are critical for the infectious process. By in silico analysis we compared the surface protein repertories of L. monocytogenes and of the non-pathogenic species Listeria innocua and identified a gene encoding a surface protein of L. monocytogenes absent in L. innocua. This gene that we named aut encodes a protein (Auto) of 572 amino acids containing a signal sequence, a N-terminal autolysin domain and a C-terminal cell wall-anchoring domain made up of four GW modules. We show here that the aut gene is expressed independently of the virulence gene regulator PrfA and encodes a surface protein with an autolytic activity. We provide evidence that Auto is required for entry of L. monocytogenes into cultured non-phagocytic eukaryotic cells. The low invasiveness of an aut deletion mutant correlates with its reduced virulence following intravenous inoculation of mice and oral infection of guinea pigs. During infection, the autolytic activity of Auto may also be critical. Auto appears thus as a novel type of L. monocytogenes virulence factor.
Unité des Interactions Bactéries Cellules, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris cedex 15, France.
Didier
D
Cabanes
Olivier
O
Dussurget
Pierre
P
Dehoux
Pascale
P
Cossart
D000595:Amino Acid Sequence; D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001921:Brain / Q000382:microbiology; D002460:Cell Line; D005057:Eukaryotic Cells / Q000382:microbiology*; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D007422:Intestines / Q000382:microbiology; D008089:Listeria monocytogenes / Q000472:pathogenicity* / Q000502:physiology*; D008088:Listeriosis / Q000382:microbiology*; D008099:Liver / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000382:microbiology; D014774:Virulence
D001426:Bacterial Proteins; D008565:Membrane Proteins; C487832:Auto autolysin, Listeria monocytogenes; D009238:N-Acetylmuramoyl-L-alanine Amidase