Molecular basis of splicing regulation by a special group of RNA elements at the intron ends

从酵母菌到人类，不同的物种是如何进化成如此复杂多样的？未来的环境变化又将如何影响这种进化？这个过程的一个关键步骤显然是从酵母到人类的基因分裂成片段，这样片段（称为外显子和内含子）可以选择性地与其他外显子一起使用，根据需要从单个基因产生多种基因产物（mRNA或蛋白质）（称为替代前mRNA剪接）。这一基因调控的基本生化步骤对基因产物的多样性做出了巨大贡献。尽管已经在不同的物种中进行了研究，但它是如何进化的以及潜在的分子基础在很大程度上仍然未知。研究剪接中内含子RNA元素进化的一个障碍是，鱼类和人类等遥远物种之间缺乏进化守恒，这使得追踪它们的进化变化变得困难。我的NSER发现基金支持的研究项目是了解基因如何通过替代pre-mRNA剪接进化产生多种RNA和蛋白质产物。在过去的10年里，我实验室的学员（主要是硕士和博士生）发现了一组叫做REPAG的特殊控制RNA元素，这使我们能够追踪它们在酵母、鱼类和人类等不同物种中的变化。这项工作已经证明了它们在一千多个物种/菌株中的进化变化，以及从单个基因产生多种蛋白质的重要性。在这个提案中，我和我的学生计划利用最先进的生化和分子生物学技术探索REPAG控制选择性剪接的新分子机制。一旦完成，这项工作将为我们了解剪接控制及其进化提供以前未知的分子细节，在生物化学、分子生物学、生物技术和健康等领域具有广泛的影响。此外，它还将帮助我们更好地预测高等生物的剪接将如何进化，以及这种进化将如何受到环境变化的影响。

How have different species evolved to such diverse complexities ranging from yeast to humans? And how will the evolvement be shaped by future environmental changes? One key step in this process is apparently the breakup of genes into pieces from yeast to humans, so that the pieces (called exons and introns) could be selectively used with other exons as needed to generate diverse gene products (mRNA or proteins) from a single gene (called alternative pre-mRNA splicing). This fundamental biochemical step of gene regulation contributes greatly to gene product diversity. Though it has been studied in different species, how it has evolved and the underlying molecular basis remain largely unknown. One obstacle in studying the evolvement of intronic RNA elements in splicing is the lack of evolutionary conservation between distant species such as fish and humans, making it difficult to track their evolutionary changes. The research program supported by my NSER discovery grant is to understand how genes have evolved to produce diverse RNA and protein products through alternative pre-mRNA splicing. In the past 10 years, trainees (mostly MSc and PhD students) in my laboratory have uncovered a special group of controlling RNA elements called REPAG that allowed us to track their changes through diverse species from yeast, fish to humans. The work has demonstrated their evolutionary changes among more than a thousand species/strains and the importance in generating multiple proteins from a single gene. In this proposal, I and my students plan to explore novel molecular mechanisms for the REPAG control of alternative splicing using state-of-the-art biochemical and molecular biology techniques. Once finished, the work will provide previously unknown molecular details for us to understand splicing control and its evolution with widespread impact on such areas as biochemistry, molecular biology, biotechnology, and health. Moreover, it will also help us to better predict how splicing in higher organisms are going to evolve and how the evolvement is going to be affected by changes in the environment.