A Salmonella typhimurium virulence gene linked to flg.

AUTOR(ES)

Carsiotis, M

RESUMO

Isogenic pairs of strains of Salmonella typhimurium which differed only in whether or not they were flagellate were found to be equally virulent in C57BL/6J mice infected orally, intravenously, or intraperitoneally. Therefore, we investigated the genetic basis for our previous observation that in this mouse model, nonflagellate delta flagABCDE25 strains were reduced in virulence compared with isogenic wild-type flagellate strains. The recombinant plasmid pMH6, which contains several flg+ genes and a segment of the S. typhimurium chromosome adjacent to the flg genes, was introduced into a delta flgABCDE25 mutant. This restored virulence in mice challenged intraperitoneally, which suggested that a virulence gene occurs adjacent to the flg genes. When plasmid pMH64, which lacks the chromosomal segment adjacent to the flg genes, was introduced into the same delta flgABCDE25 mutant, virulence was not restored. In contrast, the introduction of pMH71, a plasmid which retains the chromosomal segment adjacent to the flg genes, restored virulence. We concluded that a hitherto unknown virulence gene, which we have named mviS, occurs adjacent to the flg genes and that its absence in delta flgABCDE25 mutants, rather than the nonflagellate phenotype of the delta flgABCDE25 mutants, caused the previously reported attenuation of such mutants.

Documentos Relacionados

• Mutation of flgM attenuates virulence of Salmonella typhimurium, and mutation of fliA represses the attenuated phenotype.
• Flk Couples flgM Translation to Flagellar Ring Assembly in Salmonella typhimurium
• Salmonella typhimurium phoP virulence gene is a transcriptional regulator.
• Molecular characterization of flgM, a gene encoding a negative regulator of flagellin synthesis in Salmonella typhimurium.
• The Salmonella typhimurium virulence plasmid encodes a positive regulator of a plasmid-encoded virulence gene.