Proteinaceous infectious particles causing mammalian transmissible spongiform encephalopathies or prions are being extensively studied. However due to their hazardous nature, the initial screening of potential anti-prion drugs is often made in a yeast-based screening system utilizing a well-characterized [PSI+] prion (amyloid formed by the translation termination factor Sup35p). In the [PSI+] prion screening system (white/red colony assay), the prion phenotype yields white colonies while addition of an anti-prion drug will yield red colonies. However, this system has some limitations. It is difficult to quantify the effectiveness of the anti-prion compound, the diffusion of the studied compound may affect the result, and the deficiency of glutathione in cells may prevent the formation of red pigment in cured cells. Therefore, alternative yeast prion screening systems are still needed. This article aims to present an alternative yeast-based system to evaluate anti-prion activity of chemical compounds. The method that was used is based on an artificial [LEU2+] prion created by fusing Leu2p with the prion-forming domain of Sup35p in Saccharomyces cerevisiae. Phenotypic analysis and semi-denaturating detergent agarose gel electrophoresis (SDD-AGE) confirmed the presence of the artificial [LEU2+] prion in yeast cells. This screening system verified the anti-prion activity of 3 drugs that were found to have been active in the white/red colony assay, while one compound (6-chlorotacrine) that was active in the white/red colony assay was found to be inactive in the [LEU2+] system. This new system also appears to be more sensitive than the white/red colony assay.

中文翻译：

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基于人工[LEU2 +] ion病毒的酿酒酵母中抗-病毒药物筛选系统。

引起哺乳动物可传播的海绵状脑病或病毒的蛋白质感染性颗粒已得到广泛研究。但是，由于其危险性，潜在的抗-病毒药物的初始筛选通常是在酵母中进行的，该筛选系统使用特征明确的[PSI +] ion病毒（由翻译终止因子Sup35p形成的淀粉样蛋白）进行筛选。在[PSI +] ion病毒筛选系统（白色/红色菌落测定）中，the病毒表型产生白色菌落，而添加抗-病毒药物将产生红色菌落。但是，该系统有一些局限性。难以量化抗-病毒化合物的有效性，所研究化合物的扩散可能会影响结果，而细胞中谷胱甘肽的缺乏可能会阻止固化细胞中红色颜料的形成。所以，仍然需要替代的酵母病毒筛选系统。本文旨在介绍一种可替代的基于酵母的系统，以评估化合物的抗-病毒活性。使用的方法基于通过将Leu2p与酿酒酵母中Sup35p的病毒形成域融合而创建的人工[LEU2 +] ion病毒。表型分析和半变性去污剂琼脂糖凝胶电泳（SDD-AGE）证实了酵母细胞中存在人工[LEU2 +] pr病毒。该筛选系统验证了在白/红菌落测定中被发现具有活性的3种药物的抗pr病毒活性，而在白/红菌落测定中被发现具有活性的一种化合物（6-氯他克林）被发现没有活性。在[LEU2 +]系统中。这个新系统似乎也比白色/红色菌落测定法更灵敏。