Structural homeostasis and the assembly of a bacterial nanomachine

 描述（由申请人提供）：细菌在其细胞表面构建精细的纳米机器，与其环境相互作用并引起疾病。每台机器都必须由特定的部件组装而成，顺序正确，数量精确。在这里，我们建议研究的机制，鞭毛丝，哈格，稳态控制自己的合成和管理自己的组装在枯草芽孢杆菌的结构蛋白。Hag是三节点负反馈环的一部分，包括FliW和高度保守的毒力基因表达转录后调节因子CsrA。我们将确定FliW拮抗CsrA的机制，我们将确定CsrA和FliW的NMR溶液结构，分别和复杂。我们将研究一个内部反馈回路，其中鞭毛蛋白转录有助于维持CsrA-FliW化学计量。我们将测量细丝长度和伸长速率的细胞学参数，确定反馈调节如何影响每个参数，并探索另一种结构蛋白FlgE鞭毛钩亚基的稳态调节。我们的工作将为纳米机器组装的转录后调控建立新的范式，并为毒力基因调控因子的起源和进化提供新的见解。我们将推进B。枯草杆菌作为鞭毛研究的模式生物，我们使用B。枯草芽孢杆菌作为一个遗传平台的表达和研究异源调节剂从遥远的相关病原菌。最后，我们已经分离出当加入到全细胞中时拮抗CsrA的药物，将抗CsrA药物表征为候选抗菌治疗剂。

 DESCRIPTION (provided by applicant): Bacteria build elaborate nanomachines on their cell surface to interact with their environment and cause disease. Each machine must be assembled from specific parts, in the proper order, and in precise amounts. Here we propose to study the mechanism by which a structural protein of the flagellar filament, Hag, homeostatically controls its own synthesis and governs its own assembly in Bacillus subtilis. Hag is part of a three-node negative feedback loop including FliW and the highly conserved post-transcriptional regulator of virulence gene expression, CsrA. We will determine the mechanism by which FliW antagonizes CsrA and we will determine the NMR solution structures of CsrA and FliW, separately and in complex. We will study an internal feedback loop in which the flagellin transcript helps maintain CsrA-FliW stoichiometry. We will measure the cytological parameters of filament length and elongation rate, determine how feedback regulation contributes to each parameter, and explore homeostatic regulation in another structural protein, the FlgE flagellar hook subunit. Our work will establish new paradigms for the post-transcriptional regulation of nanomachine assembly and provide new insights into the origin and evolution of virulence gene regulators. We will advance B. subtilis as a model organism for flagellar research and we use B. subtilis as a genetic platform for the expression and study of heterologous regulators from distantly related pathogenic bacteria. Finally, we have isolated drugs that antagonize CsrA when added to whole cells will characterize the anti-CsrA drugs as candidate antibacterial therapeutics.