CAREER:RNA conformational dynamics in the regulation of microRNA biogenesis

RNA是三大生物大分子之一，对所有已知的生命形式(以及DNA和蛋白质)都是必不可少的。虽然多年来人们一直认为RNA在细胞中只有三个主要角色，但现在人们知道，RNA所扮演的角色要广泛得多，也更有趣。MicroRNAs是一类进化上保守的非编码小RNA。它们调控着超过60%的蛋白质基因，并在所有生物过程中起着关键的调节作用。由于它们在基因调控中的核心作用，microRNAs本身受到严格的调控。该项目将研究两个不同的microRNA中的构象动力学如何控制特定蛋白质辅助因子的识别，以调节它们的加工路径。该项目的结果将为这些重要基因调控因子的调控提供重要的机械学见解。该项目将扩展目前关于RNA-蛋白质相互作用的知识，并加深对RNA构象动力学在生物学中的功能作用的理解。该项目将把研究和教育结合起来，以支持对本科生和研究生以及在STEM原则中代表性不足的高中生进行科学培训和教育。将为高中生开发一个校园计划，以年度科学论坛和暑期研究实习为特色。将向当地高中开展外展活动，以发展创新的STEM教学方法。MicroRNA生物产生是一个动态和规范的过程。在典型的生物发生过程中，初级和前体microRNAs的顶环区起着关键的调节作用。然而，这些RNA元件具有高度的灵活性，无法通过传统的结构生物学技术进行高分辨率的结构研究。核酸核磁共振波谱的最新进展，包括来自等电点的核磁共振波谱，为表征高度柔性RNA的复杂构象动力学和转变开辟了新的途径。该项目将进一步开发和应用这些核磁共振方法，以及生化和计算方法，以了解microRNA生物发生通过特定的RNA-蛋白质相互作用调节的机制。以microRNA-1和microRNA-21为模型系统，本项目将可视化microRNA前体中的RNA构象动力学，并阐明蛋白质辅因子在microRNA生物发生中调节作用的结构和分子基础。结果将被用来评估该项目的中心假设，即初级和前体microRNAs的顶环区域动态采样不同的构象以进行蛋白质识别，并且这些动力学可能被调节以影响蛋白质-RNA相互作用以指导生物发生途径。

RNA is one of the three major biological macromolecules that are essential for all known forms of life (along with DNA and proteins). While for many years RNA was believed to have only three major roles in the cell, it is now known that the roles adopted by RNA are much broader and interesting. MicroRNAs are a class of evolutionarily conserved, small noncoding RNAs. They regulate more than 60% of all protein genes, and serve as critical regulators in all biological processes. Due to their central role in gene regulation, microRNAs themselves are tightly regulated. This project will investigate how conformational dynamics in two distinct microRNAs control recognition of specific protein cofactors to regulate their processing pathways. Results of this project will provide important mechanistic insights into the regulation of these essential gene regulators. This project will expand the current knowledge of RNA-protein interactions and deepen the understanding of the functional roles of RNA conformational dynamics in biology. Research and education will be integrated in this project to support scientific training and education of undergraduate and graduate students as well as underrepresented high-school students in STEM principles. An on-campus program will be developed for high-school students featuring an annual scientific forum and summer research internships. Outreach activities to local high schools will be carried out to develop innovative STEM teaching approaches.MicroRNA biogenesis is a dynamic and regulated process. During the canonical biogenesis pathway, the apical-loop regions of primary and precursor microRNAs play critical regulatory roles. However, these RNA elements are highly flexible and have evaded high-resolution structural study by conventional structural biology techniques. Recent developments in nucleic acid NMR spectroscopy, including those from the PI, have opened new avenues to characterize complex conformational dynamics and transitions in highly flexible RNAs. This project will further develop and apply these NMR methods, together with biochemical and computational approaches, to understand the mechanism by which microRNA biogenesis is regulated via specific RNA-protein interactions. Using microRNA-1 and microRNA-21 as model systems, this project will visualize RNA conformational dynamics in microRNA precursors and elucidate the structural and molecular basis for the regulatory roles of protein cofactors in microRNA biogenesis. Results will be used to evaluate the central hypothesis of this project that the apical-loop regions of primary and precursor microRNAs dynamically sample distinct conformations for protein recognition and that these dynamics may be tuned to affect protein-RNA interactions to direct biogenesis pathways.