RESUMEN
Objective To explore the function of gene phoN1 in Shigella flexneri.Method Using the λ-Red recombi-nant system, phoN1was knocked out from S.flexneri 2a strain 301.Comparative proteomics was performed to analyze the differences between mutant and wild-type strains in protein expression profiles .Sereny tests and competitive infection assays were carried out to compare the virulence of mutant and wild-type strains .Results The deletion mutant of phoN1 was suc-cessfully constructed .No significant difference between the two strains was found in the comparative proteomics analyses . The function of gene phoN1 might be unrelated to the invasion ability of S.flexneri according to the results of Sereny tests and competitive infection assays .Conclusion Gene phoN1 might be of no use for the in vitro survival and host cell invasion of S.flexneri.