RNA regulation associated with mcr11-abmR locus in M. tuberculosis

项目总结 结核分枝杆菌(Mtb)在感染过程中适应宿主相关环境 调节基因表达。而转录因子(TF)是最广为人知的 细菌基因表达的调节器，基于RNA的因子，调节基因在 对MTB的了解较少。这个项目的长期目标是定义基本的 结核分枝杆菌的基因调控机制，特别关注RNA的作用。这个 该项目的目标是定义与以下两种产品相关的核转录调控机制 结核分枝杆菌abmR-mcr11基因座：原型SRNA Mcr11和双功能RNA 结合Tf AbmR，这是稳定表达mcr11所必需的。我们将检验这一假设 Mcr11的多个不同区域通过碱基配对与靶基因调控基因表达 MRNA序列，并表征了Mcr11调控在结核分枝杆菌中的影响。基因的稳定表达 Mcr11需要AbmR，它与ATP结合，通过以下方式促进MTB的中枢代谢 抑制孟喹酮生物合成基因Mene的表达。我们建议RNA- 介导的AbmR寡聚通过将其转化为具有39S的络合物来降低其转铁蛋白活性 另一种功能。关于RNA性质的高分辨率结构信息- AbmR复合体相互作用是识别AbmR复合体功能及其功能的关键 在结核分枝杆菌生物学中可能的作用。本研究的具体目标包括：目标1：界定 Mcr11在生物、分子和遗传水平上的调控相互作用；和目标2： 在结构和生化水平上表征RNA-AbmR相互作用的作用。 这些研究将结合高分辨率冷冻电子显微镜和战略诱变， 定义AbmR-RNA相互作用的生化和生物学方法，同时提供 对结核分枝杆菌核糖核酸介导的调控机制的基本新见解。

Project summary Mycobacterium tuberculosis (Mtb) adapts to host-associated environments during infection by modulating gene expression. While transcription factors (TFs) are the most widely recognized regulators of bacterial gene expression, RNA-based factors that modulate gene expression in Mtb are less well understood. The long term goal of this project is to define fundamental mechanisms of gene regulation in Mtb, with a particular focus on the role of RNAs. The objective of this project is to define riboregulatory mechanisms associated with two products of the abmR-mcr11 gene locus in Mtb: the prototypical sRNA Mcr11 and the dual function RNA binding TF AbmR, which is required for stable mcr11 expression. We will test the hypothesis that multiple distinct regions of Mcr11 regulate gene expression by base pairing with target mRNA sequences, and characterize the impact of Mcr11 regulation in Mtb. Stable expression of Mcr11 requires AbmR, which binds ATP and contributes to central metabolism in Mtb by repressing expression of the menaquinone biosynthesis gene menE. We propose that RNA- mediated oligomerization of AbmR reduces its TF activity by converting it to a 39S complex with an alternate function. High resolution structural information regarding the nature of the RNA- AbmR complex interaction is critically needed to identify AbmR complex functions and its possible roles in Mtb biology. The specific aims of this research include: Aim 1: Define regulatory interactions of Mcr11 at the biological, molecular and genetic levels; and Aim 2: Characterize the roles of RNA-AbmR interactions at the structural and biochemical levels. These studies will combine high resolution cryo-electron microscopy with strategic mutagenesis, biochemical and biological approaches to define AbmR-RNA interactions while providing fundamental new insights into RNA-mediated regulatory mechanisms in Mtb.