鼠伤寒沙门菌BaeSR对氟喹诺酮类药物耐药性的调控机制  

Regulation Mechanism of BaeSR on Fluoroquinolones Resistance in Salmonella Typhimurium

作　　者：张临 卢芳 付恒峰 姜西迪 魏祺灵 漆彩丽 高海侠 李琳[1] ZHANG Lin;LU Fang;FU Hengfeng;JIANG Xidi;WEI Qiling;QI Caili;GAO Haixia;LI Lin(College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China)

机构地区：[1]安徽农业大学动物科技学院,合肥230036

出　　处：《畜牧兽医学报》2022年第3期894-903,共10页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家自然科学基金(31772802);安徽农业大学研究生创新基金(2020ysj-24)。

摘　　要：BaeSR是鼠伤寒沙门菌(Salmonella Typhimurium)中重要的双组分系统(two component system,TCS),通过调控下游靶基因的转录表达影响细菌的耐药性。本研究旨在探索BaeR过表达后,鼠伤寒沙门菌BaeSR对氟喹诺酮类药物(FQs)的耐药调控机制,寻找BaeR潜在靶基因。首先表达BaeR蛋白并纯化与验证,选取从转录组学筛选到的与耐药相关的差异表达基因(包括ompW、sodB、tolC、mdtD、spy和marR)作为BaeR潜在靶基因,结合LacZ报告基因融合试验及凝胶阻滞试验(EMSA)探究BaeSR对鼠伤寒沙门菌的耐药调控机制。结果显示:经纯化验证后,在28 ku处出现目的条带,表明BaeR蛋白成功表达。LacZ报告基因融合试验结果表明,BaeR过表达后可以正向调控ompW、sodB、tolC、mdtD、spy和marR的表达。EMSA结果表明,BaeR蛋白可以直接结合到marR的启动子区,调控marR基因的表达。在鼠伤寒沙门菌中,BaeSR可以通过正向调控靶基因ompW、sodB、tolC、mdtD、spy和marR的转录表达并直接调控marR的表达,从而影响菌株对FQs的耐药性。BaeSR is an important two component system in Salmonella Typhimurium,which affects bacterial resistance by regulating the transcription and expression of downstream target genes.The aim of this study was to explore the regulatory mechanism of BaeR overexpression in S.Typhimurium to fluoroquinolones(FQs),and to find the potential target gene of BaeR.In this study,we first expressed,purified and validated the BaeR protein,and screened the drug-related differentially expressed genes(include ompW,sodB,tolC,mdtD,spy and marR)from transcriptomics as potential target genes of BaeR.Combined with LacZ reporter gene fusion assay and electrophoretic mobility shift assay(EMSA),we studied the resistance mechanism of BaeSR to S.Typhimurium.The target band appeared at 28 ku after purification,which indicated that BaeR protein was successfully expressed.LacZ reporter gene fusion assay results show that,BaeR can positively regulate the expression of ompW,sodB,tolC,mdtD,spy and marR after overexpression.EMSA results indicate that BaeR protein can directly bind to the promoter region of marR and regulate the expression of marR gene.In conclusion,BaeSR can positively regulate the transcriptional expression of target genes ompW,sodB,tolC,mdtD,spy and marR in S.Typhimurium,and directly regulate the expression of marR,thus affecting the resistance of S.Typhimurium to FQs.

关 键 词：鼠伤寒沙门菌 BaeSR 耐药性 EMSA 

分 类 号：S852.61[农业科学—基础兽医学]