Elucidating the Role of Novel Cell Envelope Integrity Factors of Escherichia coli

细胞被膜包围并保护所有细菌，包括致病菌和有益菌。尽管细菌细胞被膜对医疗保健的重要性，但关于细胞被膜生物学仍有许多未知之处。例如，在模式生物大肠杆菌（Escherichia coli）中，研究和注释最好的细菌，1，200种预测的整合膜蛋白中有近三分之一仍然没有得到充分的表征或注释。最近，系统的遗传筛选被用来研究几乎所有已知的和假定的E.杆菌因此，许多新的功能连接被发现。我建议专注于两个新的模块的未注释的包膜基因，功能上连接到外膜（OM）和脂多糖（LPS）的生物过程。在第一个模块中，三个未注释的OM蛋白（OMPs）和一个未表征的预测周质基因显示功能的相互作用与编码OM生物发生和组装的基因。在第二个模块中，6个未注释的内膜（IM）基因与LPS转运（LPT）机制的组件相互作用。 虽然OM和LPS的生物过程是很好的研究，潜在的未表征的组件和信封的完整性或组装机之间的功能连接的分子机制仍然不清楚。在这里，我建议，通过生物化学和遗传学工具，（1）确定如何未注释的外膜蛋白和未注释的周质基因在OM的生物发生和组装功能;（2）阐明如何未注释的IM基因功能与LPT机械因素。除了揭示上述未注释基因的功能外，在更广泛的范围内，这项研究提案将大大加深我们对细胞包膜生物学的理解，并可能推动未来新型抗菌治疗方法的发展。

The cell envelope surrounds and protects all bacteria, including pathogenic and beneficial species. Despite the importance of bacterial cell envelope to healthcare, much still remains unknown about the cell envelope biology. For example, in the model organism Escherichia coli, the best studied and annotated bacterium, nearly one-third of the 1,200 predicted integral membrane proteins remain poorly characterized or unannotated. Recently, systematic genetic screens were used to study functional relationships among virtually all known and putative cell envelope genes of E. coli. As a result, many novel functional connections were uncovered. I propose to focus specifically on the two novel modules of unannotated envelope genes that are functionally linked to outer membrane (OM) and lipopolysaccharide (LPS) bioprocesses. In the first module, three unannotated OM proteins (OMPs) and an uncharacterized predicted periplasmic gene displayed functional interaction with genes encoding OM biogenesis and assembly. In the second module, six unannotated inner membrane (IM) genes interacted with the components of the LPS transport (LPT) machinery. Although OM and LPS bioprocesses are well-studied, the molecular mechanisms underlying the functional connections between the uncharacterized components and the envelope integrity or assembly machineries remain unclear. Here I propose, by means of biochemical and genetic tools, to (1) determine how the unannotated OMPs and an unannotated periplasmic gene function in OM biogenesis and assembly; and (2) elucidate how unannotated IM genes function with LPT machinery factors. In addition to uncovering the functions of the aforementioned unannotated genes, on a broader scale, this research proposal will substantially deepen our understanding of cell envelope biology, and may motivate the future development of novel antibacterial therapeutics.