TConditional ermination of Transcription in Mycobacterium tuberculosis

抗菌素耐药性(AMR)是与所有细菌感染有关的日益严重的问题，包括由结核分枝杆菌感染引起的结核病(TB)。根据世卫组织的最新估计，耐药结核病在2016年导致约24万人死亡。与大多数其他病原体不同，结核分枝杆菌不依赖于质粒传播的耐药性。相反，结核分枝杆菌表达了几种被称为外排泵的天然耐药机器，这种机器会将进入细胞的抗菌药物排泄出来。转录是将DNA复制到RNA的过程，RNA随后被解码以合成蛋白质。控制基因表达的一种方法是提前终止转录，即转录过程开始但尚未完成，这意味着没有要解码的RNA，因此没有蛋白质表达。最近，枯草杆菌、粪肠球菌和单核细胞增生性李斯特菌中的几个外排泵被证明是受条件终止调节的，类似的机制可能在包括结核分枝杆菌在内的其他细菌中也很普遍。本项目的目的是应用最新开发的基于下一代测序的方法来(1)确定结核分枝杆菌中条件终止因子的丰度，以及(2)确定结核分枝杆菌的自然耐药机制在多大程度上受这些条件终止子的控制，以及(3)抗结核药物在多大程度上控制结核分枝杆菌的整体基因表达。本项目的成功完成将有助于揭示结核分枝杆菌自然耐药的调控方面，并进一步了解抗结核药物如何促进和可能增强这种耐药。

Antimicrobial resistance (AMR) is an increasing problem pertaining to all bacterial infections, including tuberculosis (TB), caused by infection with Mycobacterium tuberculosis. According to the latest WHO estimates, drug resistant TB lead to around 240 000 deaths in 2016. Unlike most other pathogens, M. tuberculosis does not rely on plasmid-borne resistance. Instead, M. tuberculosis expresses several natural drug resistance machines called efflux pumps, which excrete anti-bacterial drugs that enter the cell. Transcription is the process of copying DNA to RNA, which is subsequently decoded to synthesise proteins. One way of controlling gene expression is by premature termination of transcription, i.e. the process of transcription is initiated but not completed, meaning there is no RNA to decode and hence no protein is expressed. However, premature termination of transcription can be regulated by physical or molecular signals, in which case it is referred to as conditional termination.Recently, several efflux pumps were shown to be regulated by conditional termination in Bacillus subtilis, Enterococcus faecalis and Listeria monocytogenes, and similar mechanisms are likely to be widespread in other bacteria including M. tuberculosis.The aim of this project is to apply very recently developed methods based on Next-generation sequencing to (1) define the abundance of conditional terminators in M. tuberculosis, and (2) determine to what extent natural resistance mechanisms in M. tuberculosis are controlled by such conditional terminators and (3) to what extent anti-TB drugs control overall gene expression in M. tuberculosis.The successful completion of this project will shed light on regulatory aspects of M. tuberculosis's natural drug resistance, and further our understanding of how anti-TB drugs may contribute to and possibly enhance this drug resistance.