A systems analysis of the translational release factor as a coordinator of termination mRNA stability and ribosome recycling

翻译释放因子作为终止 mRNA 稳定性和核糖体回收协调子的系统分析

• 批准号: BB/I020926/1
• 负责人: Ian Stansfield
• 金额: $ 38.08万
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FI020926%2F1
• 关键词: systems; analysis; translational; release; factor

Recent years have seen a host of genome sequences being completed, including of course the human genome. Each gene in a genome is used to direct the synthesis of a specific protein. It is the proteins that are the functional agents in a cell, for example acting as catalysts to speed individual chemical reactions within the cell. Information in the gene, coded as different sequences of the bases A, T, C and G, is used to make a protein in a two-stage process. First, the gene information is copied into a similar chain of bases in the form of a messenger RNA (mRNA). The mRNA, a long chain-like molecule, is then used as an information store to direct the assembly of a protein, consisting of a chain of amino acids, in a process called translation. The precise sequence of amino acids (directed by the mRNA base sequence) determines the eventual function of the protein. The amino acid sequence is defined by the mRNA sequence, which in turn is defined by the gene sequence, thus linking gene to protein. The process of translation forms the focus of this research proposal. During translation, small particles called ribosomes (themselves made of RNA and protein) travel along the mRNA, sequentially adding amino acids to make the final protein. This production line process is stopped (terminated) in response to a specific sequence of bases in the mRNA, causing the release of the completed protein. Termination is crucial for ensuring the protein made is of the correct length. It is now known that following termination, ribosomes are directed back to the beginning of the mRNA, effectively recycling them on the mRNA chain. This makes the translation process more efficient, but generates very complex ribosome traffic flow on the mRNA production line. For this reason, mathematical modelling of ribosome flow will be used in this research alongside the biochemical experimentation to help unravel the mechanisms by which translation is controlled. This proposal seeks to study translation termination for two important reasons. First, in many human genetic diseases, the affected gene (e.g cystic fibrosis, Duchenne muscular dystrophy) is mutated because it contains an additional stop codon early in the gene sequence. This has the effect of prematurely terminating translation, resulting in a shortened, non-functional protein. There is increasing interest in developing drugs that would make translation termination less accurate. This would allow the ribosome to bypass the early stop codon and reach the natural stop codon to make correct length protein. Research into the molecular mechanisms of termination, as this proposal describes, can provide crucial insight used directly in the development of drugs to treat some forms of human genetic disease. Termination is also important because associated with this process is the recycling of the ribosomes on the mRNA. After termination at the end of the message, ribosomes are actively returned to the beginning of the mRNA to make a new protein from the same template, forming a type of circular ribosomal race track; each circuit of the track results in a new protein being made. The recycling process is very poorly understood, and yet it is key to protein synthetic efficiency. By understanding how recycling works, it may be possible to boost the efficiency of protein synthesis in cells, which is crucial for the manufacture of drugs like hepatitis B vaccine and insulin, to name but two. In summary then, the process of translation termination is crucially important in the expression of genes in every cell, and thus has fundamental 'pure' research interest. It is however also a key to understand how proteins can be made efficiently in biotechnological processes important in drug manufacture, and is also an attractive target for drugs that can treat a range of extremely debilitating human genetic diseases.

近年来，已经完成了一系列基因组序列，当然包括人类基因组。基因组中的每个基因都用来指导特定蛋白质的合成。蛋白质是细胞中的功能介质，例如充当催化剂，加速细胞内的个别化学反应。基因中的信息被编码为A、T、C和G碱基的不同序列，在两个阶段的过程中用于制造蛋白质。首先，基因信息以信使RNA(MRNA)的形式被复制到类似的碱基链中。信使核糖核酸是一种长链状分子，在称为翻译的过程中，它被用作信息库，指导由氨基酸链组成的蛋白质的组装。氨基酸的精确序列(由信使核糖核酸碱基序列控制)决定了蛋白质的最终功能。氨基酸序列由信使核糖核酸序列决定，而信使核糖核酸序列又由基因序列决定，从而将基因与蛋白质联系起来。翻译过程构成了本研究方案的重点。在翻译过程中，被称为核糖体的小颗粒(本身由RNA和蛋白质组成)沿着信使核糖核酸移动，然后添加氨基酸形成最终的蛋白质。这一生产线过程因应于信使核糖核酸中特定的碱基序列而停止(终止)，从而导致完整蛋白质的释放。终止对于确保所制造的蛋白质具有正确的长度至关重要。现在已经知道，在终止之后，核糖体被定向回到信使核糖核酸的起点，有效地在信使核糖核酸链上循环它们。这使得翻译过程更有效率，但在mRNA生产线上会产生非常复杂的核糖体流量。出于这个原因，核糖体流动的数学模型将在这项研究中与生化实验一起使用，以帮助揭示翻译控制的机制。基于两个重要原因，本文试图对翻译终止进行研究。首先，在许多人类遗传病中，受影响的基因(如囊性纤维化、杜氏肌营养不良)发生突变，因为它在基因序列的早期包含一个额外的终止密码子。这会导致翻译提前终止，导致蛋白质变短，失去功能。人们对开发使翻译终止不那么准确的药物越来越感兴趣。这将允许核糖体绕过早期的终止密码子，到达自然终止密码子，以制造正确长度的蛋白质。正如这项提议所描述的，对终止的分子机制的研究可以为直接用于治疗某些形式的人类遗传病的药物的开发提供至关重要的见解。终止也很重要，因为与这一过程相关的是mRNA上的核糖体的循环。在信息结束时终止后，核糖体主动返回到mRNA的开始处，从相同的模板制造新的蛋白质，形成一种环形的核糖体赛道；轨道的每一圈都导致产生新的蛋白质。人们对回收过程知之甚少，但它是蛋白质合成效率的关键。通过了解循环的工作原理，有可能提高细胞中蛋白质合成的效率，这对生产乙肝疫苗和胰岛素等药物至关重要，仅举两例。综上所述，翻译终止的过程在每个细胞的基因表达中至关重要，因此具有基本的纯研究兴趣。然而，这也是理解如何在生物技术过程中有效地制造蛋白质的关键，而生物技术对制药至关重要，它也是治疗一系列极其虚弱的人类遗传病的药物的诱人靶点。

项目成果

The molecular aetiology of tRNA synthetase depletion: induction of a GCN4 amino acid starvation response despite homeostatic maintenance of charged tRNA levels

• DOI: 10.1101/610790
• 发表时间: 2019-04
• 期刊: Nucleic Acids Research
• 影响因子: 14.9
• 作者: Matthew R. McFarland;Matthew R. McFarland;Corina D. Keller;Brandon M. Childers;Holly Corrigall;Adélaïde Raguin;Adélaïde Raguin;M. Romano;I. Stansfield

Novel mRNA-specific effects of ribosome drop-off on translation rate and polysome profile.

• DOI: 10.1371/journal.pcbi.1005555
• 发表时间: 2017-05
• 期刊: PLoS computational biology
• 影响因子: 4.3
• 作者: Bonnin P;Kern N;Young NT;Stansfield I;Romano MC
• 通讯作者: Romano MC

Destabilization of Eukaryote mRNAs by 5' Proximal Stop Codons Can Occur Independently of the Nonsense-Mediated mRNA Decay Pathway.

5 近端终止密码子对真核生物 mRNA 的不稳定可能独立于无义介导的 mRNA 衰变途径而发生。

• DOI: 10.3390/cells8080800
• 发表时间: 2019
• 期刊: Cells
• 影响因子: 6
• 作者: Gorgoni B

Ribosome recycling induces optimal translation rate at low ribosomal availability.

• DOI: 10.1098/rsif.2014.0589
• 发表时间: 2014-09-06
• 期刊: Journal of the Royal Society, Interface
• 作者: Marshall E;Stansfield I;Romano MC
• 通讯作者: Romano MC

Ribosome traffic on mRNAs maps to gene ontology: genome-wide quantification of translation initiation rates and polysome size regulation.

• DOI: 10.1371/journal.pcbi.1002866
• 发表时间: 2013
• 期刊: PLoS computational biology
• 影响因子: 4.3
• 作者: Ciandrini L;Stansfield I;Romano MC
• 通讯作者: Romano MC