Identification of new genes involved in the virulence of Listeria monocytogenes by signature-tagged transposon mutagenesis.
Listeria monocytogenes is a gram-positive, facultative intracellular pathogen that can cause severe food-born infections in humans and animals. We have adapted signature-tagged transposon mutagenesis to L. monocytogenes to identify new genes involved in virulence in the murine model of infection. We used transposon Tn1545 carried on the integrative vector pAT113. Forty-eight tagged transposons were constructed and used to generate banks of L. monocytogenes mutants. Pools of 48 mutants were assembled, taking one mutant from each bank, injected into mice, and screened for those affected in their multiplication in the brains of infected animals. From 2,000 mutants tested, 18 were attenuated in vivo. The insertions harbored by these mutants led to the identification of 10 distinct loci, 7 of which corresponded to previously unknown genes. The properties of four loci involving putative cell wall components were further studied in vitro and in vivo. The data suggested that these components are involved in bacterial invasion and multiplication in the brain.
INSERM U-411, CHU Necker-Enfants Malades, 75730 Paris Cedex 15, France.
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N
Autret
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I
Dubail
P
P
Trieu-Cuot
P
P
Berche
A
A
Charbit
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins; D002473:Cell Wall / Q000737:chemistry; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D006801:Humans; D008089:Listeria monocytogenes / Q000235:genetics* / Q000472:pathogenicity; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016366:Open Reading Frames; D012097:Repressor Proteins / Q000235:genetics; D014407:Tumor Cells, Cultured; D014774:Virulence
D001426:Bacterial Proteins; C119069:CelR protein, bacteria; D004251:DNA Transposable Elements; D012097:Repressor Proteins