Replisome dynamics in M tuberculosis_linking persistence to genetic resistance

 描述(申请人提供)：结核病(TB)药物发现计划的一个主要目标是开发化合物，这种化合物将缩短治疗时间，同时限制引起结核分枝杆菌(Mtb)耐药菌株的出现。目前为期六个月的方案被认为是由于现有的抗结核药物无法消除结核分枝杆菌亚群的结果，这些亚群尽管保留了对所应用药物的全部遗传易感性，但对杀戮很难杀死。结核分枝杆菌“持久者”的存在，以及越来越多的耐药临床分离株的出现，反过来又提出了一个关键问题：(非遗传的)持久性和遗传性耐药性的发展之间是否存在功能联系？在这里，我们将检验这一假设，即通过控制参与DNA修复和损伤耐受的功能，分枝杆菌的SOS反应在结核分枝杆菌种群固有的异质性中发挥关键作用，因此有助于结核分枝杆菌在包括药物治疗在内的致命压力下持续存在的能力。我们还将评估SOS调节的imuA‘-imuB/dna E2“突变酶”的概念，它以前被认为与体内Mtb的存活和耐药性有关，它推动了暴露于抗生素的姐妹种群的突变，从而将持久性和遗传耐药性联系在一起。最后，我们将利用生化和靶向全细胞(TB-WCS)筛选来寻找新的化学抑制剂，使Mtb对遗传毒性应激敏感，并在体外消除药物选择压力下耐药的出现。这项完全合作的提案将利用生化、遗传和微生物技术，这将需要双方共同开发和应用。此外，它的前提是公开转让科学洞察力和技术专长，作为新合作的一部分，旨在围绕分枝杆菌DNA复制和修复的基本方面的调查建立长期合作伙伴关系，作为新型抗结核药物探索不足的目标。

 DESCRIPTION (provided by applicant): A major goal of tuberculosis (TB) drug discovery programs is the development of compounds that will reduce the duration of therapy, simultaneously limiting the emergence of drug-resistant strains of the causative agent, Mycobacterium tuberculosis (Mtb). The current six-month regimen is thought to result from the inability of existing anti-tuberculars to eliminate a sub-population of Mtb bacilli that are refracory to killing despite retaining full genetic susceptibility to the applied drugs. The existence of thee Mtb "persisters", together with the increasing emergence of drug-resistant clinical isolates, in turn raises a critical question: is there a functional link between (non-genetic) persistence and the development of genetic drug resistance? Here, we will test the hypothesis that, by controlling functions involved in DNA repair and damage tolerance, the mycobacterial SOS response plays a key role in the inherent heterogeneity of Mtb populations and, therefore, contributes to the ability of Mtb to persist in the face of lethal stresses including drug treatmen. We will also evaluate the notion that the SOS-regulated imuA'-imuB/dnaE2 "mutasome", which was previously implicated in Mtb survival and drug-resistance in vivo, drives mutagenesis in antibiotic-exposed persister populations and so links persistence and genetic resistance. Finally, we will utilize biochemical and target-based whole-cell (TB-WCS) screens to identify novel chemical inhibitors which sensitize Mtb to genotoxic stress and eliminate the emergence of resistance under drug-selective pressure in vitro. This fully collaborative proposal will utilize biochemical, genetic, and microbiological techniques that will require both partners to develop and apply. Moreover, it is predicated on the open transfer of scientific insight and technical expertise as part of a new collaboration designed to create a long-term partnership around the investigation of fundamental aspects of mycobacterial DNA replication and repair as an underexplored target for novel anti-TB agents.