Legionella dumoffii Tex-KL Mutated in an Operon Homologous to traC-traD is Defective in Epithelial Cell Invasion
doi: 10.3967/bes2016.055
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Key words:
- L. dumoffii Tex-KL /
- traC-traD operon /
- Invasion ability /
- Epithelial cells
Abstract: Objective To understand the mechanism of invasion by Legionella dumoffii.
Methods The L. dumoffii strain Tex-KL was mutated using the Tn903 derivative, Tn903dIIlacZ. After screening 799 transposon insertion mutants, we isolated one defective mutant. We then constructed the gene-disrupted mutant, KL16, and studied its invasion of and intracellular growth in HeLa and A549 cells, and in A/J mice survival experiments. The structure of traC-traD operon was analyzed by RT-PCR. Results The transposon insertion was in a gene homologous to Salmonella typhi traC, which is required for the assembly of F pilin into the mature F pilus structure and for conjugal DNA transmission. Results from RT-PCR suggested that the traC-traD region formed an operon. We found that when the traC gene was disrupted, invasion and intracellular growth of L. dumoffii Tex-KL were impaired in human epithelial cells. When mice were infected by intranasal inoculation with a traC deficient mutant, their survival significantly increased when compared to mice infected with the wild-type strain.
Conclusion Our results indicated that the traC-traD operon is required for the invasion and intracellular growth abilities of L. dumoffii Tex-KL in epithelial cells.
Citation: | QIN Tian, Iida Ken-ichiro, REN Hong Yu, ZHOU Hai Jian, Shin-ichi Yoshida. Legionella dumoffii Tex-KL Mutated in an Operon Homologous to traC-traD is Defective in Epithelial Cell Invasion[J]. Biomedical and Environmental Sciences, 2016, 29(6): 424-434. doi: 10.3967/bes2016.055 |