Bacterial Cell-Based Assays for Prion Proteins

描述（由申请人提供）：朊病毒是一种自我延续的蛋白质聚集体，首次在哺乳动物中被发现，因为它们在一组灾难性和无法治愈的神经退行性疾病（称为传染性海绵状脑病（tse））中的作用。酵母中朊病毒样现象的发现为朊病毒生物学的研究提供了一个强有力的模型系统。而不是杀死细胞，酵母朊病毒可以赋予细胞新的表型特征，通过表观遗传繁殖。到目前为止，还没有发现细菌朊病毒。然而，这可能仅仅反映了在不允许检测细胞质遗传的生物体中识别基于蛋白质的遗传元件的困难；在细菌中，交配不涉及细胞质的转移。

DESCRIPTION (provided by applicant): Prions are self-perpetuating protein aggregates that were first recognized in mammals for their role in a group of catastrophic and incurable neurodegenerative diseases known as the transmissible spongiform encephalopathies (TSEs). The discovery of a prion-like phenomenon in yeast has provided a powerful model system for the study of prion biology. Rather than killing the cell, yeast prions can confer on the cell new phenotypic traits that are propagated epigenetically. To date, no bacterial prions have been identified. However, this may simply reflect the difficulty of recognizing protein-based genetic elements in an organism that does not permit the detection of cytoplasmic inheritance; in bacteria, mating does not involve the transfer of cytoplasm. The objective of the proposed research is to develop a transcription-based assay for the conversion of protein domains to the prion state and to use such an assay as the basis for a genetic screen to identify prion-forming domains from bacteria and other organisms. The design of this assay will be informed by other transcription-based assays previously developed in the laboratory. The long-term goal of the proposed work is to mobilize bacterial genetics as a new tool to study the in vivo behavior of prion proteins, whether of bacterial origin or from eukaryotic cells. Ultimately, the use of genetically tractable model systems in both yeast and bacteria should provide insights that will be relevant to the understanding of the mammalian prion-based diseases.