肺炎克雷伯菌RcsAB蛋白对荚膜多糖相关基因wcaJ、wcaG和magA的调控关系

Regulation of Kleb siella pneumoniae RcsAB Protein on Capsular Polysaccharide Related Genes wcaJ,wcaG and magA

荚膜多糖(CPS)是肺炎克雷伯菌(Klebsiella pneumoniae)重要的毒力因子。Rcs系统是肠杆菌科(Enterobacteriacese)中重要的双组分信号转导系统,RcsAB是其中主要的转录调控蛋白。本研究选取了肺炎克雷伯菌NTUH-K2044 cps基因簇上的3个基因(wcaJ,wcaG和mag A),研究RcsAB对上述3个基因可能存在的调控关系。通过实时荧光定量PCR(RT-qPCR)技术和LacZ报告基因融合试验来确认RcsAB是否能够调控上述3个基因的转录表达。进而用凝胶阻滞试验(EMSA)验证RcsAB能否直接结合在靶基因的启动子区,对靶基因进行直接调控。结果表明RcsAB能够正向调控上述3个基因的转录表达,EMSA的结果提示RcsAB对这3个基因可能是通过间接的方式进行调控。RcsAB蛋白可能通过间接调控荚膜多糖基因wcaJ、wcaG和mag A的转录,从而影响菌株的荚膜多糖表型。

Capsular polysaccharide(CPS)is an important virulence factor of Klebsiella pneumonia.The Rcs system is an important two-component signal transduction system in Enterobacteriaceae,and RcsAB is the major transcriptional regulatory protein.In this study,three genes(wcaJ,wcaG and magA)on the K.pneumoniae NTUH-K2044 cps gene cluster were selected to study the possible regulatory relationship with RcsAB.Real-time quantitative fluorescence PCR(RT-qPCR)technology and LacZ reporter gene fusion test were used to confirm whether RcsAB could regulate the transcriptional expression of the three genes mentioned above.Then,electrophoretic mobility shift assay(EMSA)was used to verify whether RcsAB can directly bind to the promoter region of target genes for direct regulation of target genes.The results indicate that RcsAB can positively regulate the transcription and expression of the three genes mentioned above.The results of EMSA suggest that RcsAB may regulate the three genes indirectly.The RcsAB protein can affect the capsular polysaccharide phenotype of the strain by indirectly regulating the transcription of the capsular polysaccharide genes wcaJ,wcaG and mag A.