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铜绿假单胞菌中的Ⅲ型分泌系统(type Ⅲ secretion system,T3SS)与其致病性密切相关.已有研究表明,Ⅲ型分泌系统受群体感应系统Rhl系统的负调节,而喹诺酮系统(PQS)又正调节Rhl系统.前期的研究中我们获得了1个对PQS系统起负调控的调节子PmpR.综合它们之间的相互关系,本研究探讨了pmpR基因与Ⅲ型分泌系统的关系.结果表明,T3SS中的相关基因exoS,exoT,exoY和exsD在pmpR基因突变体中的表达明显增强.EMSA实验结果表明,PmpR蛋白并不能与Ⅲ型分泌系统基因启动子相结合,说明PmpR对T3SS可能起间接调节.此外,PQS系统对Ⅲ型分泌系统也起负调节.由上述结果可知,pmpR基因不可能通过PQS系统来调节T3SS系统,其调节途径中可能还存在着一些未知蛋白介导这种关系.
The type Ⅲ secretion system (T3SS) in Pseudomonas aeruginosa is closely related to its pathogenicity.Researches have shown that the type Ⅲ secretion system is negatively regulated by the Rhl system of quorum-sensing system, whereas the quinolone system (PQS ) Regulates the Rhl system.In the previous study, we obtained a regulator PmpR that negatively regulates the PQS system.In conclusion, the relationship between the pmpR gene and the type III secretion system was discussed in this study.Results The results showed that the expressions of exoS, exoT, exoY and exsD in T3SS were significantly increased in the mutant of pmpR gene.The results of EMSA showed that PmpR protein could not bind to the promoter of type Ⅲ secretion system, PQS system also plays a negative regulation on the type III secretion system.From the above results, it is not known that the pmpR gene can regulate the T3SS system through the PQS system, and some unknown proteins in the regulatory pathway may mediate this relationship.