A new genetic approach for studying prions and other pathogenic protein aggregate

摘要 Prion是一种具有感染性的、自我繁殖的蛋白质聚集体，与许多 破坏性神经退行性疾病称为传染性海绵状脑病。在人类中， 最常见的TSE是克雅氏病，通常在没有警告的情况下发作，导致一年内死亡 对90%的患者的诊断率。TSE被归因于一种特定的细胞蛋白(PrP)，该蛋白具有 有可能转变为高度结构化的、？被认为是富含片状的聚集态(称为淀粉样蛋白) 成为感染源。由于没有任何治疗方法可以影响疾病的结果或进展，新的 试验性途径至关重要。 这项拟议的研究的目标是动员细菌遗传学作为一种新的实验系统 研究普里子的行为。已经表明，大肠杆菌细胞质可以支持类普里子的形成 聚合，我们建议开发一套基于转录的遗传检测方法，可以检测到 蛋白质结构域转变为普里恩状态。利用这些分析，我们将进行突变筛选来鉴定细胞 伴侣和其他可能影响普恩过程的因素。因为地球的进化守恒 伴侣蛋白，这样的筛选可能会发现与哺乳动物疾病相关的潜在新药靶点。 我们还将使用基于细菌的遗传分析来筛选细菌基因组以及高等 生物体(包括哺乳动物)寻找新的普恩蛋白。细菌普恩病毒的发现可能会 对人类健康的深远影响，特别是在宿主-病原体相互作用的背景下。最后，我们 设想使用基于细菌的基因分析来筛选可能阻碍转化为 和/或Prion态的传播。虽然我们的主要关注点是Pron病，但我们打算开发的工具 也应适用于大量非传染性神经退行性疾病，这些疾病 与淀粉样聚集体的形成有关。

Abstract Prions are infectious, self-propagating protein aggregates that have been implicated in a number of devastating neurodegenerative diseases known as transmissible spongiform encephalopathies. In humans, the most common TSE, Creutzfeldt-Jakob disease, typically strikes without warning, leading to death within 1 year of diagnosis for 90% of patients. The TSEs have been attributed to a specific cellular protein (PrP) that has the potential to convert to a highly structured, ? sheet-rich aggregated form (referred to as amyloid) that is thought to be the infectious agent. With no therapies that can affect either the outcome or progress of the disease, new experimental avenues are crucial. The objective of the proposed research is to mobilize bacterial genetics as a new experimental system for studying prion behavior. Having shown that the E. coli cytoplasm can support the formation of prion-like aggregates, we propose to develop a set of transcription-based genetic assays that can detect conversion of protein domains to the prion state. Using these assays, we will conduct mutant screens to identify cellular chaperones and other factors that can affect the prion process. Because of the evolutionary conservation of chaperone proteins, such screens may uncover potential new drug targets relevant to mammalian disease. We will also use bacteria-based genetic assays to screen bacterial genomes as well as the genomes of higher organisms (including mammals) for novel prion proteins. The discovery of bacterial prions could have profound implications for human health, particularly in the context of host-pathogen interactions. Finally, we envision using bacteria-based genetic assays to screen for small molecules that can hinder conversion to and/or propagation of the prion state. While our primary focus is prion disease, the tools we aim to develop should also be applicable to the large number of non-infectious neurodegenerative diseases that are associated with the formation of amyloid aggregates.