Functional specialization of RNP granules in RNA metabolism

RNP 颗粒在 RNA 代谢中的功能特化

• 批准号: BB/W004488/1
• 负责人: Christopher Grant
• 金额: $ 97.71万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FW004488%2F1
• 关键词: Functional; specialization; RNP; granules; RNA

Although proteins are the principal effectors of all biological function they must first be made from a template molecule known as messenger RNA (mRNA). This process, known as translation, is a complex process that is essentially identical across all eukaryotic life (animals, plants, and fungi). The fate of mRNA molecules is therefore critically important in determining when, where and how much of each specific protein is made. Recent work has shown that many mRNAs are key components of a class of subcellular bodies known as RNA granules which have been postulated to play important roles in mRNA degradation, storage, and even the translation process itself. Indeed, these RNA-containing bodies or granules have recently been shown to play important roles in many neurodegenerative and musculodegenerative diseases such as Fragile X mental retardation, spinal muscular atrophy, Huntington's and Alzheimer's. Subcellular bodies where mRNA can be stored were first discovered over 30 years ago and are now known to come in different flavours, representing specialised compartments that can segregate specific molecules inside a cell. Unlike other organelles, they have no membranes and often arise as a consequence of a change in the physical properties of specific proteins and RNAs. So rather like oil droplets in water, the proteins and RNAs self-associate into liquid droplets that form microscopically distinct bodies. They can subsequently be distinguished by the conditions under which they form, as well as the nature of the mRNAs and proteins that coalesce into them. Stress granules (SGs) and Processing bodies (PBs) are two such examples which have served as a paradigm for these biomolecular condensates. They are thought to rationalise mRNA content under times of stress- storing useful mRNAs and possibly destroying others. However, we don't really know which mRNAs are stored, which are degraded, and more importantly what determines the individual fates of the mRNAs in these granules. This is a prerequisite to understanding their functional role in helping cells and organisms to adapt to changing conditions. In this project, we will use cutting-edge large-scale technologies to precisely define the molecular fate of the majority of the ~1400 mRNAs that we have previously shown localize to PBs. We will use a labelling technique to systematically examine the stability of the different mRNAs that are found in PBs following nutrient deprivation. Our hypothesis is that that some mRNAs are rapidly degraded in PBs to remove them from cells whilst others are more stable and provide a source of mRNAs that can rapidly resume protein production once the stress is removed. Mutagenesis approaches will be used to define the cis and trans-acting factors that control the fate of mRNAs in PBs. Whilst it is known that parts of the RNA decay machinery are found in PBs and so may promote RNA degradation, it is unknown how other mRNAs can survive in PBs essentially protected against degradation. Finally, we will examine how PBs and SGs interact to engender functionality during stress conditions, as they have traditionally been considered as distinct entities - despite many molecular components in common. Yeast is considered a simple eukaryote and so is substantially easier to study than more complex multicellular organisms. Since all of the RNA granules utilised in yeast are also present in multicellular organisms such as animals and plants, our fundamental studies in yeast will guide and inform investigations in these other systems. Therefore, as well as having implications for human disease, this work will provide alternative mechanisms to tweak industrial biotechnology expression systems where yeast and plants are commonly used. The studies in this proposal may well allow optimisation at this level, especially where stress conditions prove an important factor in the industrial scale growth of an organism.

虽然蛋白质是所有生物功能的主要效应物，但它们必须首先由称为信使RNA（mRNA）的模板分子制成。这个过程被称为翻译，是一个复杂的过程，在所有真核生物（动物，植物和真菌）中基本上是相同的。因此，mRNA分子的命运在决定每种特定蛋白质的何时、何地和多少产生方面至关重要。最近的研究表明，许多mRNA是一类称为RNA颗粒的亚细胞体的关键组分，这些颗粒被认为在mRNA降解、储存甚至翻译过程本身中发挥重要作用。事实上，这些含RNA的体或颗粒最近已被证明在许多神经变性和肌肉变性疾病如脆性X智力低下、脊髓性肌萎缩、亨廷顿氏病和阿尔茨海默氏病中起重要作用。可以储存mRNA的亚细胞体是在30多年前首次发现的，现在已知有不同的味道，代表着可以分离细胞内特定分子的专门隔室。与其他细胞器不同，它们没有膜，通常是由于特定蛋白质和RNA的物理性质发生变化而产生的。就像水中的油滴一样，蛋白质和RNA自结合成液滴，形成微观上不同的物体。它们随后可以通过它们形成的条件以及结合到它们中的mRNA和蛋白质的性质来区分。应激颗粒（SG）和加工体（PB）就是两个这样的例子，它们已成为这些生物分子凝聚物的典范。它们被认为在压力下合理化mRNA含量-储存有用的mRNA并可能破坏其他mRNA。然而，我们并不真正知道哪些mRNA被储存，哪些被降解，更重要的是，是什么决定了这些颗粒中mRNA的个体命运。这是了解它们在帮助细胞和生物体适应变化条件方面的功能作用的先决条件。在这个项目中，我们将使用尖端的大规模技术来精确地定义我们之前已经显示定位于PB的约1400种mRNA中的大多数的分子命运。我们将使用标记技术来系统地检查在营养剥夺后在PB中发现的不同mRNA的稳定性。我们的假设是，一些mRNA在PB中迅速降解，将它们从细胞中去除，而另一些mRNA则更稳定，并提供了一种mRNA来源，一旦压力被去除，这些mRNA可以迅速恢复蛋白质生产。突变方法将用于定义控制PB中mRNA命运的顺式和反式作用因子。虽然已知RNA衰变机制的一部分存在于PB中，因此可能促进RNA降解，但尚不清楚其他mRNA如何在PB中存活，基本上免受降解。最后，我们将研究PB和SG如何在应激条件下相互作用以产生功能，因为它们传统上被认为是不同的实体-尽管许多分子组分是共同的。酵母被认为是一种简单的真核生物，因此比更复杂的多细胞生物更容易研究。由于酵母中使用的所有RNA颗粒也存在于动物和植物等多细胞生物体中，因此我们对酵母的基础研究将指导并为这些其他系统的研究提供信息。因此，除了对人类疾病有影响外，这项工作还将提供替代机制来调整工业生物技术表达系统，其中酵母和植物是常用的。本提案中的研究很可能允许在这一水平上进行优化，特别是在胁迫条件证明是生物体工业规模生长的重要因素的情况下。