Abstract：Objective: To investigate the effect of OmpR on the invasion of Salmonella enterica serovar Typhi(S. Typhi) and its potential mechanism. Methods: The invasion of S. Typhi were investigated by using cell invasion experiment with the empty vector strain(WTpBAD33), the ompR deletion mutant strain(ΔompRpBAD33) and the ompR complementary strain(CΔompR). In addition, qRTPCR and EMSA were used to analyze the regulation of OmpR on the expression of invasionrelated genes iagA, invF and prgH. Results: In the invasion assay, ΔompRpBAD33 showed significantly weaker invasion than that of WTpBAD33(P<0.01)，and the invasion of CΔompR was higher than that of ΔompRpBAD33(P<0.01); expressional levels of invasionrelated genes in ΔompRpBAD33 were lower than those in WTpBAD33(P<0.01). EMSA results showed that OmpR bound to the promoter region of prgH in a dosedependent manner, but it was unable to bind to the upstream regions of iagA and invF. Conclusion: OmpR promotes the invasion of S. Typhi, which results from upregulating the expression of invasionrelated genes by directly regulating prgH, indirectly regulating iagA and invF.
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2019, Vol. 29 
