Neisseria meningitides small RNA's regulate Citric acid cycle activity under Feast and Famine conditions

We identified twin small non-coding RNAs regulating tricarboxylic acid (TCA) cycle activity in Neisseria meningitidis. Expression of TCA cycle enzymes was elevated in sRNA deletion mutants. Direct interaction between sRNAs and the ribosomal entry sites on target mRNAs was demonstrated. Expression of the sRNAs was down-regulated in cells grown in poor medium with glucose as the sole carbon source but not without lrp, indicating that sRNA expression is controlled by the stringent response. N. meningitidis, over-expressing the sRNAs replicated in blood, but not in human cerebrospinal fluid. In addition, Lrp synthesis was inhibited by direct interaction between the sRNA and the 5’ UTR of lrp. sRNAs control adaptation of N. meningitidis to variation in nutrient supply in different niches of its host.

我们在脑膜炎奈瑟菌（Neisseria meningitidis）中鉴定出一对可调控三羧酸循环（TCA循环）活性的孪生小非编码RNA（small non-coding RNAs, sRNAs）。在sRNA缺失突变菌株中，TCA循环相关酶的表达水平显著升高。研究证实，sRNAs可与靶mRNA上的核糖体进入位点发生直接相互作用。在以葡萄糖为唯一碳源的贫营养培养基中培养的菌体内，sRNAs的表达量下调，但该现象在缺失lrp的菌体中并未出现，表明sRNA的表达受严谨反应（stringent response）调控。过表达sRNAs的脑膜炎奈瑟菌可在血液中增殖，但无法在人类脑脊液中增殖。此外，sRNA与lrp的5'非翻译区（5' UTR）之间的直接相互作用可抑制Lrp的合成。sRNAs可调控脑膜炎奈瑟菌对宿主不同生态位中营养供给变化的适应性。