Elucidating the Quality Control Pathways that Cope with Mutant Ribosomal RNA in Mammalian Cells

项目摘要 蛋白质生产是绝对必要的，错误的翻译与广泛的疾病有关 包括癌症、神经变性和一类主要的发育障碍， 核糖体病为了确保遗传密码的忠实翻译，细胞需要监控 翻译装置的所有组成部分，包括mRNA、tRNA和核糖体。虽然质量 监测mRNA和tRNA的控制机制相对较好地表征，但对mRNA和tRNA的调控机制知之甚少。 核糖体本身的质量控制。真核生物的核糖体是一个复杂的分子机器， 核糖体RNA（rRNA）和80种蛋白质，所有这些成分都经历了突变，氧化应激， 和紫外线辐射。值得注意的是，rRNA在翻译过程中执行核糖体的核心酶功能。 尽管rRNA对核糖体功能和人类健康的重要性， 在哺乳动物细胞中还没有研究过如何科普有缺陷的rRNA的存在。以前在酵母中的工作 发现携带突变的rRNA优先降解，证实了质量的存在。 针对错误rRNA的控制机制。然而，参与检测和降解的组件 这些rRNA的特征仍然很差。这种知识差距主要是由于技术限制， 包括有限的rRNA检测方法和适合于全基因组筛选的适当报告系统。 最近的技术进步已经为无偏见和机械研究领域做好了准备。由于关键的 核糖体质量控制对人类健康的本质，我试图定义质量控制机制， 哺乳动物细胞传递rRNA。我设计了一种哺乳动物的荧光rRNA报告基因， 与无偏见的遗传筛查和假设驱动的方法相结合。利用这一独特的 工具，我将确定人类细胞如何科普有缺陷的核糖体窝藏突变18S rRNA，rRNA 核糖体小亚基的组成部分。我将首先描述18S rRNA突变如何干扰 翻译.其次，我将确定哺乳动物细胞中缺陷18S rRNA的命运。最后，我将确定 哺乳动物应对有缺陷的rRNA的因素。这些拟议的研究将首次描述 哺乳动物rRNA质量控制机制，并为了解失调如何提供基础 导致人类疾病。

PROJECT SUMMARY Protein production is absolutely essential and faulty translation has been linked to a wide-range of diseases including cancer, neurodegeneration and a class of predominantly developmental disorders known as ribosomopathies. In order to ensure faithful translation of the genetic code, cells need to monitor the integrity of all components of the translation apparatus, including mRNAs, tRNAs, and ribosomes. Although the quality control mechanisms that monitor mRNAs and tRNAs are relatively well characterized, very little is known about quality control of the ribosome itself. The eukaryotic ribosome is a complex molecular machine consisting of 4 ribosomal RNAs (rRNA) and 80 proteins, and all these components are subjected to mutations, oxidative stress, and UV radiation. Notably, the rRNA carries out the core enzymatic functions of the ribosome during translation. Despite the importance of rRNA to ribosomal function and human health, the quality control mechanisms that cope with the presence of defective rRNA have not been studied in mammalian cells. Previous work in yeast has discovered that rRNAs harboring mutations are preferentially degraded, confirming the existence of quality control mechanisms targeting faulty rRNA. However, the components involved in the detection and degradation of these rRNAs remain poorly characterized. This knowledge gap is primarily due to technological constraints, including limited rRNA detection methods and appropriate reporter systems geared for genome-wide screens. Recent technological advances have primed the field for unbiased and mechanistic studies. Due to the critical nature of ribosomal quality control to human health, I seek to define the quality control mechanisms that mammalian cells impart on rRNA. I have engineered a mammalian fluorescent rRNA reporter that can be paired with both unbiased genetic screening and hypothesis-driven approaches. Taking advantage of this unique tool, I will determine how human cells cope with defective ribosomes harboring mutant 18S rRNA, the rRNA component of the small ribosomal subunit. I will first characterize how mutations in the 18S rRNAs interfere with translation. Second, I will determine the fate of defective 18S rRNA in mammalian cells. Lastly, I will identify the mammalian factors coping with defective rRNA. Together, the proposed studies will for the first time delineate mammalian rRNA quality control mechanisms, and provide the foundation for understanding how dysregulation of this process leads to human disease.