单增李斯特菌谷氧还蛋白Grx负调控渗透转运系统OpuC转录

It aims to study the regulatory relationship with the transcription of genes related to the osmotic transport system (OpuC) by constructing a gene deletion strain of glutaredoxin (Grx, encoded by lmo2344) of Listeria monocytogenes (LM). The LM gene deletion strain was constructed and screened by the homologous recombination method established in our laboratory. Real - time fluorescence quantitative PCR (RT - PCR) and green fluorescent protein reporter system (FRS) were used to compare the transcriptional level regulation of genes related to the osmotic transport system (opuCA, opuCB, opuCC and opuCD) in the LM wild strain EGD - e and the grx deletion strain. The results showed that compared with the wild strain, the transcriptional levels of the osmotic transport - related genes opuCA/B/C/D in the grx gene deletion strain were extremely significantly up - regulated (more than 50 times). In addition, the fluorescence reporter system also confirmed that the deletion of the grx gene did lead to the enhanced promoter activity of the above - regulated genes, thereby promoting the significant up - regulation of the gene transcription. This study first indicated that the LM Grx system is involved in the transcriptional regulation of the osmotic transport system OpuC, but the molecular mechanism involved in this process remains to be further explored. This study is helpful for in - depth understanding of the regulatory relationship between the important redox system of LM and other stress tolerance - related regulatory proteins, as well as the molecular mechanism by which bacteria adapt to the external environment and infect the host through participating in biological processes, and is of great significance for preventing and controlling food - borne intracellular bacterial infections and ensuring human public health.

旨在通过构建单增李斯特菌(Listeria monocytogenes,LM)谷氧还蛋白(glutaredoxin,Grx,由lmo2344编码)的基因缺失株以研究其与渗透转运系统(OpuC)相关基因转录的调控关系。LM基因缺失株采用本实验室已建立的同源重组方法构建并筛选获得。利用实时荧光定量PCR(RT-PCR)和绿色荧光蛋白报告系统(FRS)比较LM野生株EGD-e和grx缺失株对渗透转运系统相关基因(opuCA、opuCB、opuCC和opuCD)的转录水平调控。结果表明,与野生株相比,grx基因缺失株中渗透转运相关基因opuCA/B/C/D的转录水平极显著上调(50倍以上)。此外,荧光报告系统也证实grx基因缺失确实导致上述被调控基因的启动子活性增强进而促使该基因转录明显上调。本研究首次表明LM Grx系统参与了渗透转运系统OpuC的转录调控,但该过程涉及的分子机制尚待深入探究。本研究有助于深入理解LM重要的氧化还原系统与其他应激耐受调控相关蛋白之间的调控关系,以及通过参与生物学过程介导细菌体外环境适应及宿主内感染的分子机制,对于防控食源性胞内菌感染和保障人类公共卫生具有重要意义。