Understanding how RNA interacting proteins modulate the translatability of mRNAs

细胞受其基因组的支配，基因组是所有基因产物(蛋白质和RNA)的遗传蓝图，这些基因产物执行支撑生命的无数生物功能。然而，理解“部件列表”只是通向完全了解细胞如何工作的必要的第一步。复杂的行为，如对环境刺激的反应，生长和分裂，或分化和特化成特定的组织，都受到严格的监管。这是通过控制基因何时“开启”和“关闭”来实现的，通常是在复杂的途径和网络中。我们现在知道，在基因调控过程中有几个重要的控制点，因为温度、营养物质和环境中其他因素的变化会影响细胞的行为。这项提议关注的是在每个细胞中制造(或合成)所有新蛋白质所需的一组蛋白质，这一过程被称为“翻译”。这些“蛋白质合成因子”将编码基因序列的信使分子RNA翻译成蛋白质分子。每个细胞中有数以千计的RNA分子，每个分子携带一种不同蛋白质的指令(或编码)。蛋白质合成因子必须以正确的方式与每一种RNA相互作用，以便每一种新的蛋白质都以正确的比例正确地合成。通过改善我们对正常细胞中这种过程如何工作的基本理解，它可以帮助科学家了解这种过程被改变的疾病，或者病毒等病原体如何能够劫持植物、动物或人类细胞并导致传染病。在这个提案中，我们解决了一个广泛的问题，即蛋白质合成因子是如何知道在任何时候解码哪些RNA的？我们和其他人发现，每一种不同RNA的丰度都不能很好地预测它所编码的蛋白质的丰度。这意味着必须有一个主动的选择或选择过程来挑选要在任何时候翻译的RNA。对于少数RNA来说，已知它们包含帮助控制其使用的特定元素。此外，细胞中还存在其他蛋白质，它们可以与RNA结合，影响它们的使用地点和时间。然而，目前对几乎所有RNA的细节都知之甚少，即使在最简单的细胞内也是如此。在这项提案中，我们将使用遗传上顺从的单细胞生物体面包师和酿酒酵母(酿酒酵母)来解决这个问题。我们将采取广泛的方法，利用现代技术来研究与RNA相互作用的蛋白质，以控制它们何时被翻译。然后我们将通过挑选具体的例子来更详细地研究机械方面的问题。我们将提供证据，说明哪些RNA受哪组蛋白质因子控制，哪些对特定应激条件的反应重要。

Cells are governed by their genomes, the genetic blueprint for all the gene products (proteins and RNAs) that carry out the myriad of biological functions that underpin life. Understanding the 'parts list' is however, only the first necessary step towards a complete understanding of how cells work. Complex behaviours such as responding to environmental stimuli, growing and dividing, or differentiating and specialising into a given tissue are tightly regulated. This is achieved by controlling when genes are turned 'on' and 'off', often in complex pathways and networks. We now know that there are several important control points in the process of gene regulation, as changes in temperature, nutrients and other factors in the environment influence how cells behave. This proposal focuses on one group of proteins that are required to make (or synthesize) all new proteins in each cell, a process referred to as 'translation'. These 'protein synthesis factors' translate RNA, a messenger molecule that encode gene sequences, into protein molecules. There are many thousands of RNA molecules in each cell, each one carrying instructions (or coding) for a different protein. The protein synthesis factors must interact with each RNA in the right way so that each new protein is made correctly and in the correct proportions. By improving our fundamental understanding of how such processes work in normal cells it can help scientists understand diseases in which this process is altered, or how agents such as viruses are able to hijack plant, animal or human cells and cause infectious diseases. In this proposal we address the broad question of how is it that the protein synthesis factors know which RNAs to decode at any one time? We and others have found that the abundance of each different RNA present is a poor predictor for the abundance of the protein that it encodes. This means that there must be an active choice or selection process to pick which RNAs are to be translated at any one time. For a few RNAs it is known that they contain specific elements that help control their use. Also that there are other proteins present in cells that can bind to RNAs to influence where and when they are used. However at the present time very few details are known for almost all RNAs even within the simplest cells. In this proposal we will address this issue using the genetically amenable single celled organism bakers and brewers yeast (Saccharomyces cerevisae). We will take a broad approach using modern technologies to study proteins that interact with RNAs to control when they are translated. We will then follow this by picking specific examples to study in greater mechanistic detail. We will provide evidence for which RNAs are controlled by which set of protein factors and which are important for responding to specific stress conditions.