Understanding double-stranded RNA recognition in human cells

项目摘要 双链RNA（dsRNA）结构的特异性识别是关键的生物学基础。 从发育到抗病毒免疫反应的过程，并涉及大量的dsRNA- 结合蛋白生物化学和结构研究已经描述了这些蛋白质如何相互作用 但是它们在细胞中遇到的dsRNA要复杂得多。而且小 关于细胞如何调节dsRNA识别是已知的。我实验室的目标是了解 dsRNA结合蛋白与细胞中的天然dsRNA相互作用，将生物化学模型连接起来。 dsRNA识别到细胞dsRNA识别和调控。未来五年，我们将 专注于microRNA（miRNA）生物合成和先天免疫传感中的dsRNA识别。 在miRNA生物合成过程中，微处理器识别并切割来自 长转录物称为初级miRNA（pri-miRNAs）。我之前的研究建立了一个统一的模型 发现一个最佳的miRNA发夹结构可以增强一个 次优的miRNA发夹在相同的转录本上-称为簇辅助。因为几乎 40%的人类miRNAs以簇的形式存在，其中许多与疾病有关，并受到 集群援助，我们建议剖析这种基本的调控机制，在miRNA 使用生物化学、单分子和结构方法的生物发生。dsRNA的识别 通过先天免疫传感器如RIG-I和MDA 5启动抗病毒反应。最近的研究 显示内源性dsRNA也可以激活这些传感器，有时导致 自身炎症和自身免疫性疾病。因此，自我dsRNA的识别需要 受到修饰、降解或屏蔽内源性dsRNA的蛋白质的限制。充分发挥两国 在dsRNA识别和加工方面，我们将1）开发新的生物化学方法， 鉴定先天免疫传感器的dsRNA配体，和2）开发新的遗传筛选方法 以确定先天免疫中限制自身dsRNA传感的因素。这些研究将 提供了关于细胞dsRNA如何被感知和调节的重要见解， 对癌症、自身免疫性疾病和传染病的影响。

PROJECT SUMMARY Specific recognition of double-stranded RNA (dsRNA) structures underlies key biological processes from development to antiviral immune responses, and involves a host of dsRNA- binding proteins. Biochemical and structural studies have delineated how these proteins interact with model ligands, yet dsRNAs that they encounter in cells are far more complex. Moreover, little is known about how cells regulate dsRNA recognition. The goal of my lab is to understand how dsRNA-binding proteins interact with natural dsRNAs in cells, connecting biochemical models of dsRNA recognition to cellular dsRNA recognition and regulation. In the next five years, we will focus on dsRNA recognition in microRNA (miRNA) biogenesis and innate immune sensing. During miRNA biogenesis, Microprocessor recognizes and cleaves hairpin-like structures from long transcripts called primary miRNAs (pri-miRNAs). My previous research built a unifying model of human pri-miRNA and discovered that an optimal miRNA hairpin enhances the cleavage of a suboptimal miRNA hairpin on the same transcript—known as cluster assistance. Because nearly 40% of human miRNAs reside in clusters, with many implicated in diseases and influenced by cluster assistance, we propose to dissect this fundamental regulatory mechanism in miRNA biogenesis using biochemical, single-molecule, and structural approaches. Recognition of dsRNA by innate immune sensors such as RIG-I and MDA5 initiates antiviral responses. Recent studies show that endogenous dsRNAs can also activate these sensors, sometimes resulting in autoinflammatory and autoimmune diseases. The recognition of self dsRNAs therefore needs to be restricted by proteins that modify, degrade or shield endogenous dsRNAs. Building on our expertise in dsRNA recognition and processing, we will 1) develop new biochemical methods to identify dsRNA ligands of innate immune sensors, and 2) develop new genetic screen methods to identify factors that restrict self dsRNA sensing in innate immunity. Together these studies will provide crucial insights into how cellular dsRNAs are sensed and regulated, with therapeutic implications for cancer, autoimmune and infectious diseases.