tRNA biology in healthy ageing: Functional differentiation and expression of tRNAiMet loci in Drosophila.

健康老龄化中的 tRNA 生物学：果蝇中 tRNAiMet 位点的功能分化和表达。

• 批准号: BB/Y000919/1
• 负责人: Nazif Alic
• 金额: $ 70.98万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FY000919%2F1
• 关键词: tRNA; biology; healthy; ageing; Functional

The proportion of older people in our societies is rapidly increasing. For many, older age comes with increased frailty, impaired function and increased susceptibility to disease. The ageing of our populations is incurring massive personal and socioeconomic costs that need to be urgently addressed.Ageing itself can be modulated. Understanding this plasticity presents us with an opportunity to devise interventions to improve human health into old age. Importantly, directly targeting ageing has the potential for broad health improvements not limited to a single disease.This research project will answer a fundamental question in the biology of transfer RNAs (tRNAs) with strong relevance to ageing. tRNAs are the adaptor molecules universally used to translate the genetic code into proteins. Our interest in tRNA biology comes from our work on understanding the molecular mechanisms whereby the activity of a key regulator of cellular protein synthesis, the Target of Rapamycin Kinase Complex 1 (TORC1), promotes animal ageing. We found that TORC1 acts though RNA polymerase III, which itself is responsible for generating tRNAs. Hence, understanding tRNA biology will advance our knowledge of the ageing process.100s of tRNA genes are present in animal genomes, often as copies of identical sequence, complicating the analysis of their biology. Historically, such identical copies were thought to be simply redundant, providing multiple templates to facilitate high expression levels required for protein synthesis. However, there is growing appreciation that placing tRNA copies in different genomic contexts has allowed animals to finetune tRNA expression patterns thus diversifying organismal functions of identical or similar tRNAs. This hypothesis remains experimentally unaddressed due to lack of suitable animal models and genetic reagents, despite its fundamental importance. The fruit fly is a small animal but a powerful experimental model that has proven utility in understanding the basic biology of animals, including humans, and how they age. To start probing into the organismal roles of tRNAs, we focused on a tRNA specialised for initiation of protein synthesis, the initiator tRNAMet (tRNAiMet). We generated a set of fly mutants deleting copies of tRNAiMet from four different genomic locations. Our preliminary phenotyping revealed at least one tRNAiMet locus that contributes to ageing and indicated an interplay of unique and redundant organismal functions for the four loci. We will use this set of mutants, together with a set of reporter lines we have generated, to answer a fundamental question in tRNA biology, which will help us understand ageing: Why are multiple, identical copies of tRNA genes present throughout an animal's genome?Firstly, we will perform extensive phenotyping of single mutants and their combinations to identify organismal functions that are unique to certain loci as well as those that are redundant, with focus on ageing. Secondly, we will use reporter lines to assess the expression from each locus during development and in different adult tissues and organs. We will correlate the two sets of findings as well as integrate them by formally testing if unique expression patterns drive unique organismal functions. Thirdly, we will examine the role of tRNAiMet loci in the plasticity of ageing. Specifically, we will determine if longevity resulting from a reduction in nutrient intake or TORC1 inhibition is in part caused by changes in tRNAiMet levels.The project will answer a fundamental question in tRNA biology to provide us with a step change in understanding of tRNAs in the context of animal physiology. It will provide us with a pioneering insight into their role in animal ageing, as well as the knowledge required to decipher their organismal functions downstream of TORC1. In turn, this knowledge will inform interventions aimed at ensuring human health throughout the life course.

我们社会中老年人的比例正在迅速增加。对于许多人来说，年龄越大，身体越虚弱，功能受损，对疾病的敏感性也越高。人口老龄化正在造成巨大的个人和社会经济成本，需要紧急解决。老龄化本身是可以调节的。了解这种可塑性为我们提供了制定干预措施以改善人类老年健康的机会。重要的是，直接针对衰老具有广泛改善健康的潜力，而不仅限于单一疾病。该研究项目将回答与衰老密切相关的转移 RNA (tRNA) 生物学中的一个基本问题。 tRNA 是普遍用于将遗传密码翻译成蛋白质的接头分子。我们对 tRNA 生物学的兴趣来自于我们对细胞蛋白质合成关键调节因子雷帕霉素激酶复合物 1 (TORC1) 靶标的活性促进动物衰老的分子机制的研究。我们发现 TORC1 通过 RNA 聚合酶 III 起作用，RNA 聚合酶 III 本身负责生成 tRNA。因此，了解 tRNA 生物学将增进我们对衰老过程的了解。动物基因组中存在数百个 tRNA 基因，通常是相同序列的副本，这使得对其生物学的分析变得复杂化。从历史上看，这种相同的拷贝被认为是多余的，提供了多个模板以促进蛋白质合成所需的高表达水平。然而，人们越来越认识到，将 tRNA 拷贝置于不同的基因组环境中可以使动物微调 tRNA 表达模式，从而使相同或相似 tRNA 的生物功能多样化。尽管这一假设具有根本重要性，但由于缺乏合适的动物模型和遗传试剂，该假设在实验上仍未得到解决。果蝇是一种小动物，但却是一种强大的实验模型，已被证明有助于了解包括人类在内的动物的基本生物学以及它们如何衰老。为了开始探究 tRNA 的生物作用，我们重点研究了一种专门用于启动蛋白质合成的 tRNA，即起始子 tRNAMet (tRNAiMet)。我们生成了一组果蝇突变体，从四个不同的基因组位置删除了 tRNAiMet 的副本。我们的初步表型分析揭示了至少一个导致衰老的 tRNAiMet 位点，并表明这四个位点独特和冗余的生物功能之间的相互作用。我们将使用这组突变体以及我们生成的一组报告系来回答 tRNA 生物学中的一个基本问题，这将有助于我们了解衰老：为什么动物的基因组中存在多个相同的 tRNA 基因副本？首先，我们将对单个突变体及其组合进行广泛的表型分析，以确定某些基因座特有的有机体功能以及冗余的有机体功能，重点关注衰老。其次，我们将使用报告系来评估发育过程中以及不同成体组织和器官中每个基因座的表达。我们将关联两组发现，并通过正式测试独特的表达模式是否驱动独特的有机体功能来整合它们。第三，我们将研究 tRNAiMet 位点在衰老可塑性中的作用。具体来说，我们将确定因营养摄入减少或 TORC1 抑制而导致的长寿是否部分是由 tRNAiMet 水平的变化引起的。该项目将回答 tRNA 生物学的一个基本问题，使我们对 tRNA 的理解发生重大变化。动物生理学背景。它将为我们提供关于它们在动物衰老中的作用的开创性见解，以及破译它们在 TORC1 下游的有机功能所需的知识。反过来，这些知识将为旨在确保人类整个生命过程健康的干预措施提供信息。