Increased [PSI+] Appearance by Fusion of Rnq1 with the Prion Domain of Sup35 in Saccharomyces cerevisiae
Increased [PSI+] Appearance by Fusion of Rnq1 with the Prion Domain of Sup35 in Saccharomyces cerevisiae
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DOI：
10.1128/ec.00353-08
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发表时间：
2009-07-01
期刊：
影响因子：
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通讯作者：
Seok, Yeong-Jae
中科院分区：
文献类型：
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作者：
Choe, Young-Jun;Ryu, Yangkyun;Seok, Yeong-Jae
在繁殖过程中，酵母朊病毒显示出严格的序列偏好，赋予朊病毒组装的特异性。虽然[PSI+]和[RNQ（+）]的传播是相互独立的，但[PSI+]的出现是由[RNQ（+）]的存在所促进的。为了解释[RNQ（+）]对[PSI+]外观的影响，提出了交叉播种模型，其中Rnq1聚集体充当Sup35聚集体的不完美模板。如果在酵母细胞的细胞质中发生交叉接种事件，则Rnq1聚集体和Sup35之间的碰撞频率将影响[PSI+]的外观。在这项研究中，为了解决是否在体内发生交叉接种，开发了一种新的[PSI+]诱导方法，该方法利用Sup35（NM）和Rnq1的朊病毒结构域之间的蛋白融合。该融合蛋白成功地加入预先存在的Rnq1聚集体，这应该导致NM在Rnq1聚集体周围的定位，从而增加NM和Rnq1聚集体之间的碰撞频率。即使融合蛋白的表达水平较低，[PSI+]的出现也可以被非常有效地诱导。这项研究支持Sup35和Rnq1之间的体内交叉接种的发生，并提供了一个新的工具，可用于解剖的机制，从头出现的朊病毒。
During propagation, yeast prions show a strict sequence preference that confers the specificity of prion assembly. Although propagations of [PSI+] and [RNQ(+)] are independent of each other, the appearance of [PSI+] is facilitated by the presence of [RNQ(+)]. To explain the [RNQ(+)] effect on the appearance of [PSI+], the cross-seeding model was suggested, in which Rnq1 aggregates act as imperfect templates for Sup35 aggregation. If cross-seeding events take place in the cytoplasm of yeast cells, the collision frequency between Rnq1 aggregates and Sup35 will affect the appearance of [PSI+]. In this study, to address whether cross-seeding occurs in vivo, a new [PSI+] induction method was developed that exploits a protein fusion between the prion domain of Sup35 ( NM) and Rnq1. This fusion protein successfully joins preexisting Rnq1 aggregates, which should result in the localization of NM around the Rnq1 aggregates and hence in an increased collision frequency between NM and Rnq1 aggregates. The appearance of [PSI+] could be induced very efficiently, even with a low expression level of the fusion protein. This study supports the occurrence of in vivo cross-seeding between Sup35 and Rnq1 and provides a new tool that can be used to dissect the mechanism of the de novo appearance of prions.