Structural and functional aspects of the small riboregulator 6S RNA

转录组对营养限制和再供应的适应是细菌的一个基本过程，特别是在自然栖息地。细菌6S RNA是一种普遍存在的生长期依赖性核糖核酸转录调节因子，它与RNA聚合酶（RNAP）结合，在营养物质缺乏时抑制转录。在营养补充后，当核苷三磷酸水平增加时，RNAP通过从作为模板的6S RNA转录短RNA（pRNA）而充当RNA依赖性RNA聚合酶，导致6S RNA/RNAP复合物的解离和6S RNA的降解。尽管大多数细菌表达单一的6S RNA种类，但枯草芽孢杆菌编码两种具有相似二级结构但具有不同表达谱的6S RNA（6S-1和6S-2）。我们证明了B. subtilis 6S-1 RNA与E.而6S-2 RNA的功能似乎不同。现在，主要的努力方向是：（a）了解两个B的不同作用。枯草杆菌6S RNA，（B）了解6S RNA敲除的表型，（c）了解6S-1 RNA功能循环各个步骤的分子基础，（d）了解6S-1 pRNA合成如何与B中的GTP库相关。枯草芽孢杆菌中的pRNA以及6S RNA和RelA调控途径如何相互交叉，（e）分析B中是否存在pRNA。枯草芽孢杆菌具有额外的转录后功能。

Adaptation of the transcriptome to nutrient limitation and resupply is a fundamental process in bacteria, particularly in natural habitats. Bacterial 6S RNA, a ubiquitous and growth phase-dependent riboregulator of transcription, binds to RNA polymerase (RNAP) and inhibits transcription when nutrients are low. Upon nutrient resupply, when nucleoside triphosphate levels increase, RNAP acts as an RNA-dependent RNA polymerase by transcribing short RNAs (pRNAs) from 6S RNA as template, leading to dissociation of 6S RNA/RNAP complexes and degradation of 6S RNA. Whereas the majority of bacteria express a single 6S RNA species, Bacillus subtilis encodes two 6S RNAs (6S-1 and 6S-2) of similar secondary structure, but with different expression profiles. We have shown that B. subtilis 6S-1 RNA shares many functional hallmarks with the prototypic 6S RNA from E. coli, whereas 6S-2 RNA appears to function differently. Now, major efforts will be directed towards: (a) understanding the differential roles of the two B. subtilis 6S RNAs, (b) understanding the phenotypes of 6S RNA knockouts, (c) understanding the molecular basis of the individual steps of the 6S-1 RNA functional cycle, (d) understanding how 6S-1 pRNA synthesis is related to the GTP pool in B. subtilis and how the 6S RNA and RelA regulatory pathways are interdigitated, (e) analysis if pRNAs in B. subtilis have additional posttranscriptional functions.