Glover J R, Kowal A S, Schirmer E C, Patino M M, Liu J J, Lindquist S
Howard Hughes Medical Institute, Department of Molecular Genetics and Cell Biology, The University of Chicago, Illinois 60637, USA.
Cell. 1997 May 30;89(5):811-9. doi: 10.1016/s0092-8674(00)80264-0.
The [PSI+] factor of S. cerevisiae represents a new form of inheritance: cytosolic transmission of an altered phenotype is apparently based upon inheritance of an altered protein structure rather than an altered nucleic acid. The molecular basis of its propagation is unknown. We report that purified Sup35 and subdomains that induce [PSI+] elements in vivo form highly ordered fibers in vitro. Fibers bind Congo red and are rich in beta sheet, characteristics of amyloids found in certain human diseases, including the prion diseases. Some fibers have distinct structures and these, once initiated, are self-perpetuating. Preformed fibers greatly accelerate fiber formation by unpolymerized protein. These data support a "protein-only" seeded polymerization model for the inheritance of [PSI+].
酿酒酵母的[PSI+]因子代表了一种新的遗传形式：改变的表型的胞质传递显然基于改变的蛋白质结构而非改变的核酸的遗传。其传播的分子基础尚不清楚。我们报告称，在体内诱导[PSI+]元件的纯化的Sup35及其亚结构域在体外形成高度有序的纤维。纤维结合刚果红且富含β折叠，这是在某些人类疾病（包括朊病毒疾病）中发现的淀粉样蛋白的特征。一些纤维具有独特的结构，一旦形成便会自我延续。预先形成的纤维极大地加速了未聚合蛋白的纤维形成。这些数据支持了[PSI+]遗传的“仅蛋白质”种子聚合模型。
