Defining redundant strategies central to Legionella replication vacuole formation

项目摘要 传染病是全球人类健康的主要威胁。的出现 抗生素抗性病原体需要开发新的药物来治疗感染。一 开发抗生素的根本挑战是许多病原体在宿主体内复制， 使它们无法接触到抗微生物剂。病原体的关键过程 在宿主细胞中的生长代表了治疗干预的最有希望的新靶点。 大多数在宿主细胞内生长的细菌病原体都是在一个专门的隔室中生长的 叫做复制泡。复制泡的形成和维持是 对细菌的生存和生长至关重要，因为它提供了营养来源和保护 针对检测和消除病原体的宿主监测系统。破坏这个过程 从而限制细菌负荷并使宿主能够杀死病原体。尽管至关重要的 复制液泡生物发生的作用，负责的机制知之甚少。 确定病原体如何产生和维持复制的主要障碍 液泡是多余的。细菌通过将细菌蛋白分泌到 宿主细胞调节多种宿主生物学过程。当分泌机器 本身是疾病所必需的，个别分泌的蛋白质是不稳定的。这种情况经常发生 因为一种分泌蛋白的活性可以补偿另一种蛋白的损失。然而，在这方面， 许多病原体还采用多种策略来产生复制泡。 由于蛋白质的缺乏，很难确定单个分泌蛋白在疾病中的作用 从而为新抗生素找到有希望的靶点。 我们开发了一种基因筛选技术， 分泌的蛋白质的细菌病原体军团菌，原因是一个危及生命的 肺炎我们已经定义了一组分泌蛋白，它们在细胞内参与相同的策略。 复制液泡的形成和单独的，但冗余的策略，用于实现这一点 任务这项研究的目的是确定构成一个 单一策略促进复制空泡形成，独立策略如何促进 以及它们如何相互补偿。这项工作将提供前所未有的 深入了解决定感染结果的关键事件，以及开发新的 预防和治疗疾病的策略。

PROJECT SUMMARY Infectious disease is a major threat to human health worldwide. The emergence of antibiotic resistance pathogens necessitates the development of new drugs to treat infection. A fundamental challenge in developing antibiotics is that many pathogens replicate inside host cells rendering them inaccessible to antimicrobial agents. Critical processes for pathogen growth in host cells represent the most promising new targets for therapeutic intervention. Most bacterial pathogens that grow inside host cells do so in a specialized compartment called the replication vacuole. The formation and maintenance of a replication vacuole are paramount to bacterial survival and growth as it provides a source of nutrients and protection against host surveillance systems that detect and eliminate pathogens. Disrupting this process would thus limit bacterial burden and enabling pathogen killing by the host. Despite the crucial role of replication vacuole biogenesis, the mechanisms responsible are poorly understood. A major obstacle in determining how a pathogen generates and sustains a replication vacuole is redundancy. Bacteria form a replication vacuole by secreting bacterial proteins into the host cell to modulate a variety of host biological processes. While the secretion machinery itself is essential for disease, individual secreted proteins are dispensable. This often occurs because the activity of one secreted protein can compensate for the loss of another. However, many pathogens also employ multiple strategies for generating a replication vacuole. Redundancy makes it very difficult to define the roles of individual secreted proteins in disease and thus, identify promising targets for new antibiotics. We have developed a genetic screening technique to resolve redundancy amongst secreted proteins of the bacterial pathogen Legionella, the cause of a life-threatening pneumonia. We have defined sets of secreted proteins that contribute to the same strategy in replication vacuole formation and separate but redundant strategies used to accomplish this task. The goal of this research is to determine how individual components that constitute a single strategy promote replication vacuole formation, how independent strategies contribute to this process and how they compensate for one another. This work will provide unprecedented insight into a critical event determining the outcome of an infection and a means to develop new strategies to prevent and treat disease.