长双歧杆菌染色体上的基因BLJ_864和BLJ_865构成的Ⅱ型毒素—抗毒素系统  

A type Ⅱ toxin-antitoxin system encoded by BLJ_864 and BLJ_865 in chromosome of Bifidobacterium longum

作　　者：韦艳霞[1,2] 叶露[2] 刘佃滨[3] 郭晓奎[2] 

机构地区：[1]徐州医学院病原生物学与免疫学教研室,徐州221004 [2]上海交通大学基础医学院病原生物学教研室,上海200025 [3]徐州医学院口腔医学院,徐州221004

出　　处：《上海交通大学学报（医学版）》2014年第9期1319-1324,共6页Journal of Shanghai Jiao tong University:Medical Science

基　　金：国家自然科学基金(31300029);江苏省自然科学基金(BK20130213);江苏省高校"青蓝工程"优秀青年骨干教师项目;徐州医学院优秀人才科研启动基金(D2012014)~~

摘　　要：目的鉴定Bifidobacterium longum JDM301(B.longum JDM301)染色体上的BLJ_864、BLJ_865是否构成mazEF家族的一组Ⅱ型毒素—抗毒素系统(TA系统)。方法通过RT-PCR分析BLJ_864和BLJ_865在B.longum JDM301以及E.coli中的共转录;通过将带有BLJ_864和BLJ_865的完整操纵子的质粒转化入E.coli,证明同一操纵子中的BLJ_864、BLJ_865所编码的抗毒素蛋白和毒素蛋白共表达;通过在E.coli中单独表达BLJ_864编码的毒素蛋白或将其与BLJ_865编码的抗毒素蛋白共表达,鉴定BLJ_864编码的毒素蛋白对细菌生长的抑制作用及其对应的BLJ_865编码的抗毒素蛋白能否消除毒素蛋白的生长抑制作用。结果 BLJ_864和BLJ_865构成一个二元操纵子,两者在其天然菌株B.longum JDM301中可以共转录;异丙基-β-D硫代半乳糖苷(IPTG)诱导下,BLJ_864和BLJ_865所编码的抗毒素蛋白和毒素蛋白在异源宿主E.coli中共表达。BLJ_864编码的毒素蛋白的表达抑制异源宿主E.coli的生长,而将BLJ_865所编码的抗毒素蛋白与BLJ_864编码的毒素蛋白共表达则可以拮抗毒素蛋白的生长抑制作用。结论 B.longum JDM301基因组中的假定基因BLJ_864和BLJ_865编码一组有功能的、隶属mazEF家族的Ⅱ型TA系统。Objective To identify whether the BLJ_864 and BLJ_865 in the chromosome of Bifutobacterium longum JDM301 （B. longum JDM301） constitute a type Ⅱ toxin-antitoxin system （TA system） of mazEF family. Methods The co-transcription of BLJ_864 and BLJ_865 in B./ongum JDM301 and E. coli was analyzed by the RT-PCR. The co-expression of BLJ_864 and BLJ_865 encoded antitoxin protein and toxin protein in the intact operon that carried BLJ_864 and BLJ_865 was proved by transforming the plasmid, which carried the operon, into the E. coli strain. The inhibition effect of BLJ_864 encoded toxin protein on the growth of E. coli cells and the corresponding effect of BLJ_865 encoded antitoxin protein on removing the inhibition effect were identified by the expression of BLJ_864 encoded toxin protein or co-expression of the toxin protein and BLJ_865 encoded antitoxin protein in E. coli. Results BLJ 864 and BLJ_865 constituted a dual operon and could co-transcript in the natural strain of B. longumJDM301. BLJ_864 encoded toxin protein and BLJ_865 encoded antitoxin protein could co-express in the heterologous host of E. coli when induced by isopropyl-[^-D-thiogalactopyranoside （IPTG）. The expression of BLJ_864 encoded toxin protein inhibited the growth of E. coli, while the coexpression of BLJ_864 encoded toxin protein and BLJ_865 encoded antitoxin protein could antagonize the inhibition effect of toxin protein. Conclusion BLJ_864 and BLJ_865 in the chromosome of B./ongumJDM301 encode a functional type ⅡTA system of mazEF family.

关 键 词：毒素—抗毒素系统 长双歧杆菌 mazEF 

分 类 号：Q933[生物学—微生物学]