Listeria monocytogenes mutants lacking phosphatidylinositol-specific phospholipase C are avirulent.
A number of bacterial species secrete phosphatidylinositol-specific phospholipase C (PI-PLC). In this report, we show that the facultative intracellular bacterial pathogen, Listeria monocytogenes, contains a gene, plcA, predicting a polypeptide with 31% amino acid identity to a Bacillus thuringiensis PI-PLC. Accordingly, L. monocytogenes secretes PI-PLC activity, while a mutant with a transposon insertion in plcA lacks detectable PI-PLC activity. In addition, expression of plcA in B. subtilis resulted in secretion of PI-PLC activity. The L. monocytogenes PI-PLC-defective mutant was three logs less virulent for mice and failed to grow in host tissues. The mutant was also defective for in vitro growth in mouse peritoneal macrophages. These results strongly suggest that PI-PLC is an essential determinant of L. monocytogenes pathogenesis. Whether the PI-PLC acts on a bacterial or host substrate remains to be determined.
Camilli
A
A
Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 19104.
Goldfine
H
H
Portnoy
D A
DA
D000818:Animals; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D005798:Genes, Bacterial; D008089:Listeria monocytogenes / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D008088:Listeriosis / Q000382:microbiology / Q000503:physiopathology; D008099:Liver / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D013154:Spleen / Q000382:microbiology; D014774:Virulence / Q000235:genetics
D015345:Oligonucleotide Probes; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase