BsrE/SR5: a novel type I toxin-antitoxin system in Bacillus subtilis: Localization of the toxin and identification of its cellular target(s), mechanism(s) of antitoxin action, and biological functions of the system

毒素/抗毒素系统(TA系统)是一对相邻的基因，其中一个编码稳定的毒肽，被邻近基因编码的不稳定的抗毒素中和。目前，已知的TA系统有5种。在I型TA系统中，抗毒素是一种小的调节性RNA，它与毒素mRNA相互作用，相互作用导致抑制毒素翻译或/和毒素mRNA的降解。尽管早在很久以前就已经研究和阐明了质粒编码的TA系统的功能(它们是分离后的杀伤系统，即它们导致无质粒细胞的死亡)，但染色体I型TA系统的生物学功能和重要性仍然是一个推测。在本项目中，我们计划从三个方面对枯草芽孢杆菌新的I型TA系统进行研究：1)毒素的细胞定位、细胞靶标(S)及其生化活性。作为一项创新，我们将使用细胞生物学的尖端技术来识别毒素目标。2)RNA抗毒素的作用机制3)该系统对枯草芽孢杆菌的生物学功能/重要性。

Toxin/antitoxin systems (TA systems) are pairs of adjacent genes, one of which encodes a stable toxic peptide that is neutralized by an unstable antitoxin coded by the neighbouring gene. Currently, 5 types of TA systems are known. In type I TA systems, the antitoxin is a small regulatory RNA, which interacts with the toxin mRNA, and interaction results in inhibition of toxin translation or/and degradation of the toxin mRNA. Whereas the function of plasmid-encoded TA systems has been investigated and elucidated a long time ago (they are post-segregational killing systems, i.e. they cause the death of plasmid free cells), the biological function and importance of chromosomal type I TA systems is still a matter of speculation. In this project, we plan to investigate a new chromosome-encoded type I TA system from Bacillus subtilis, bsrE/SR5, with regard to three aspects: 1) Cellular localization of the toxic peptide, its cellular target(s) and its/their biochemical activities. As a novelty, we will use cutting-edge techniques from cell biology to identify toxin targets. 2) Mechanism of action of the RNA antitoxin 3) Biological function/importance of this system for Bacillus subtilis.