Müller Peter, Jahn Natalie, Ring Christiane, Maiwald Caroline, Neubert Robert, Meißner Christin, Brantl Sabine
a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany.
RNA Biol. 2016 May 3;13(5):511-23. doi: 10.1080/15476286.2016.1156288. Epub 2016 Mar 3.
bsrE/SR5 is a type I TA system from prophage-like element P6 of the B. subtilis chromosome. The 256 nt bsrE RNA encodes a 30 aa toxin. The antitoxin SR5 is a 163 nt antisense RNA. Both genes overlap at their 3' ends. Overexpression of bsrE causes cell lysis on agar plates, which can be neutralized by sr5 overexpression, whereas deletion of the chromosomal sr5 copy has no effect. SR5 is short-lived with a half-life of ≈7 min, whereas bsrE RNA is stable with a half-life of >80 min. The sr5 promoter is 10-fold stronger than the bsrE promoter. SR5 interacts with the 3' UTR of bsrE RNA, thereby promoting its degradation by recruiting RNase III. RNase J1 is the main RNase responsible for SR5 and bsrE RNA degradation, and PnpA processes an SR5 precursor to the mature RNA. Hfq stabilizes SR5, but is not required for its inhibitory function. While bsrE RNA is affected by temperature shock and alkaline stress, the amount of SR5 is significantly influenced by various stresses, among them pH, anoxia and iron limitation. Only the latter one is dependent on sigB. Both RNAs are extremely unstable upon ethanol stress due to rapid degradation by RNase Y.
bsrE/SR5是来自枯草芽孢杆菌染色体类前噬菌体元件P6的I型毒素-抗毒素系统。256个核苷酸的bsrE RNA编码一种30个氨基酸的毒素。抗毒素SR5是一种163个核苷酸的反义RNA。这两个基因在其3'端重叠。bsrE的过表达会导致琼脂平板上的细胞裂解，而sr5的过表达可使其中和，而染色体上sr5拷贝的缺失则没有影响。SR5半衰期约为7分钟，寿命较短，而bsrE RNA半衰期大于80分钟，较为稳定。sr5启动子比bsrE启动子强10倍。SR5与bsrE RNA的3'非翻译区相互作用，从而通过招募核糖核酸酶III促进其降解。核糖核酸酶J1是负责SR5和bsrE RNA降解的主要核糖核酸酶，PnpA将SR5前体加工成成熟RNA。Hfq可稳定SR5，但对其抑制功能并非必需。虽然bsrE RNA受温度冲击和碱性应激影响，但SR5的量受多种应激显著影响，其中包括pH值、缺氧和铁限制。只有后者依赖于sigB。在乙醇应激下，由于核糖核酸酶Y的快速降解，这两种RNA都极其不稳定。
