Functional characterization of RelBE toxin-antitoxin system in probiotic Bifidobacterium Iongum JDM301  

作　　者：Yanxia Wei Lu Ye Yang Li Fan Yang Dianbin Liu Xiaokui Guo Renxian Tang Chang Liu 

机构地区：[1]Department of Pathogenic Biology and Immunology, Laboratory of Infection and Immunity/School of Stomatology,Xuzhou Medical University, Xuzhou 221004, China [2]Department of Microbiology and Immunity, Shanghai Jiao Tong University Scheel of Medicine, Shanghai 200025, China

出　　处：《Acta Biochimica et Biophysica Sinica》2016年第8期741-749,共9页生物化学与生物物理学报（英文版）

基　　金：This work was supported by the grants from the National Natural Science Foundation of China （Nos. 31300029 and 31400001）, the Natural Science Foundation of Jiangsu Province, China （No. BK20130213）, the Scientific Research Foundation for the Talents of Xuzhou Medical College （No. D2012014） and the Qing Lan Project of Jiangsu Province, China.

摘　　要：Toxin-antitoxin （TA） systems are widespread in bacteria and archaea. However, the roles of chro- mosomally encoded TA systems in bacterial physiology are still open to debate. In this study, a TA module-relBE in Bifidobacterium Iongum JDM301 （relBE^Bif） was identified and its function in stress response was evaluated. Bioinformatics analysis of the whole genome sequences of JDM301 revealed a pair of linked genes encoding a RelBE-like TA system （RelBE^Bif）. Our results revealed a bicistronic operon formed by relBE^Bif in JDM301. Over-expression of RelE^Bif had a toxic effect on Escherichia coil, which could be neutralized by co-expression of its cognate antitoxin, RelB^Bif. Our data also demonstrated that RelEBif is an mRNA interferase and that the activity of RelEBif can be inhibited by RelB^Bif. These results suggest that RelEa^Bif is a toxic nuclease which arrests cell growth through mRNA degradation, and that the activity of RelE^Bif can be abolished by co-expression of RelB^Bif. In addition, we also found that the expression of RelBE^Bif is increased during osmotic stress, suggesting that RelBE^Bif is activated under this adverse condition. Our results imply that the RelBE^Bif TA module may represent a cell growth modulator which helps B. Iongum to deal with osmotic stress.Toxin-antitoxin （TA） systems are widespread in bacteria and archaea. However, the roles of chro- mosomally encoded TA systems in bacterial physiology are still open to debate. In this study, a TA module-relBE in Bifidobacterium Iongum JDM301 （relBE^Bif） was identified and its function in stress response was evaluated. Bioinformatics analysis of the whole genome sequences of JDM301 revealed a pair of linked genes encoding a RelBE-like TA system （RelBE^Bif）. Our results revealed a bicistronic operon formed by relBE^Bif in JDM301. Over-expression of RelE^Bif had a toxic effect on Escherichia coil, which could be neutralized by co-expression of its cognate antitoxin, RelB^Bif. Our data also demonstrated that RelEBif is an mRNA interferase and that the activity of RelEBif can be inhibited by RelB^Bif. These results suggest that RelEa^Bif is a toxic nuclease which arrests cell growth through mRNA degradation, and that the activity of RelE^Bif can be abolished by co-expression of RelB^Bif. In addition, we also found that the expression of RelBE^Bif is increased during osmotic stress, suggesting that RelBE^Bif is activated under this adverse condition. Our results imply that the RelBE^Bif TA module may represent a cell growth modulator which helps B. Iongum to deal with osmotic stress.

关 键 词：Bifidobacterium Iongum toxin-antitoxin module osmotic stress TUFA 

分 类 号：Q959.226.4[生物学—动物学] TS201.3[轻工技术与工程—食品科学]