Phage mimicry of mycobacterial signaling

描述(申请人提供)：结核分枝杆菌比任何其他单一传染病病原体造成的人类死亡更多，并在全球范围内造成相当大的社会和经济损失。众所周知，成人肺结核很难控制，需要长期使用多种抗生素进行治疗。缺乏对这些方案的依从性，助长了多种耐药结核分枝杆菌菌株的出现。 结核病的有效控制需要更好的诊断方法、更有效的疫苗和更好的抗分枝杆菌药物，特别是在治疗潜伏和多重耐药感染方面。分枝杆菌遗传学的最新进展和几个分枝杆菌全基因组序列的获得为阐明分枝杆菌生理学、新陈代谢、遗传学和结构的基本原理将导致控制分枝杆菌感染的新策略带来了巨大的希望。目前，我们对这些核心问题的基本方面的分子基础知之甚少，比如为什么这些细菌生长如此缓慢，它们独特的细胞壁是如何合成的，以及分枝杆菌细胞是如何交流的。回答这些核心问题对于理解分枝杆菌发病的分子基础以及我们如何干预它是重要的。 噬菌体是了解其细菌宿主的强大工具，对于分枝杆菌噬菌体也是如此。分枝杆菌噬菌体是与宿主关系极其密切的伙伴；它们不仅依赖宿主的新陈代谢机制进行复制和组装，而且还必须通过复杂和敌对的分枝杆菌细胞壁进入，并在细胞对它们不再有任何用处时找到退出细胞的方法。此外，分枝杆菌噬菌体可能根本不会杀死它们的宿主，但会将它们的DNA整合到宿主染色体中，并和平共存。 这个项目的重点是研究分枝杆菌噬菌体模拟分枝杆菌细胞信号通路的方式。我们已经发现，分枝杆菌噬菌体Bxb1整合到了groEL1基因中，groEL1基因是分枝杆菌中两个GroEL基因之一。GroEL1基因的中断导致生物膜成熟的丧失，显然是由于无法组装Fas-II酶复合体来合成Mycolate。我们建议阐明GroEL1在生物膜形成和霉菌酸合成中的特定作用，并确定其在结核分枝杆菌发病机制中的作用。

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis is responsible for more human deaths than any other single infectious agent and imposes a considerable social and economic toll on a global scale. Adult pulmonary tuberculosis is notoriously difficult to control, requiring extended treatments with multiple antibiotics. Lack of compliance with these regimens has encouraged the appearance of multiple drug-resistant strains of M. tuberculosis. Effective control of tuberculosis requires better diagnostic methods, more efficacious vaccines, and better anti-mycobacterial drugs, particularly for treatments of latent and multi-drug resistant infections. Recent advances in mycobacterial genetics and the availability of several whole mycobacterial genome sequences brings considerable promise to the idea that elucidating the fundamental tenets of mycobacterial physiology, metabolism, genetics and structure will lead to novel strategies for controlling mycobacterial infections. Currently, we know little about the molecular basis of the fundamental aspects of such central questions as to why these bacteria grow so slowly, how is their unique cell wall synthesized, and how do mycobacterial cells communicate. Answering these central questions is important to understanding the molecular basis of mycobacterial pathogenesis and how we might intervene in it. Bacteriophages are powerful tools for understanding their bacterial hosts, and this is certainly true for the mycobacteriophages. Mycobacteriophages are partners in an extremely intimate relationship with their hosts; they are not only dependent on the host metabolic machinery for their replication and assembly, but they must also gain entry through a complex and hostile mycobacterial cell wall, and find ways to exit the cell once it is no longer of any use to them. Furthermore, mycobacteriophages may not kill their hosts at all but integrate their DNA into the host chromosome and co-exist peacefully. This project focuses on examining ways in which mycobacteriophages mimic the cellular signaling pathways of the mycobacteria. We have discovered that mycobacteriophage Bxbl integrates into the groEL1 gene, one of two groEL genes in the mycobacteria. Interruption of the groEL1 gene leads to the loss of biofilm maturation, apparently due to the inability to assemble the FAS-II enzyme complex for mycolate synthesis. We propose to elucidate the specific role of GroEL1 in biofilm formation and mycolic acid synthesis, and to determine its role in the pathogenesis of Mycobacterium tuberculosis.