Self-Assembly and Packaging of RNA and DNA in Viruses and Virus-like Particles

通过这笔赠款，生命过程化学计划支持加州大学洛杉矶分校化学和生物化学系的William M.Gelbart教授和Charles M.Knobler教授对病毒自组装和包装过程的体外研究。该项目由生物局分子和细胞生物科学司遗传机制专题组共同资助。对于dsDNA的情况，用噬菌体lambda进行单粒子实验是为了验证这样一个假设，即压力驱动的基因组喷射可以通过RNA聚合酶转录等活跃过程来完成。对于单链RNA的情况，选择了一种特定的简单植物病毒属，即特征良好的溴病毒作为模型系统。将进行实验来测量广泛的单链RNA分子的相对包装效率，包括病毒和非病毒分子，以发现RNA电荷、大小和形状所扮演的竞争角色。此外，为了了解这些植物病毒与现代哺乳动物病毒(如甲型病毒和黄病毒)之间的进化联系，将试图用植物衣壳蛋白包装这些哺乳动物RNA基因组，并用磷脂双层包裹产生的核衣壳，以模拟登革热和丙型肝炎等被包裹的病毒。在基本水平上，这项研究试图为物理上理解病毒的传染性奠定坚实的基础。“物理病毒学”这一新兴领域正在为培养新的跨学科科学学生和研究人员做出贡献，他们具备将化学和物理的基本思想、方法和技术应用于病毒复制等基本生物学问题的能力。向非理科本科专业的学生教授了两门关于病毒一般方面的新课程，并为当地高中学生和教师开发了一个外展计划，让他们接触到加州大学洛杉矶分校的病毒相关研究，并为课堂提供建模和可视化项目。从长远来看，这一基础研究可能有助于基于干扰单链RNA/衣壳蛋白核衣壳的自组装和/或其被脂膜包裹的新方法来进行抗病毒治疗。

With this grant, the Chemistry of Life Processes program is supporting the research of Professors William M. Gelbart and Charles M. Knobler in the Department of Chemistry and Biochemistry at UCLA on in vitro investigations of viral self-assembly and packaging processes. This project is being co-funded by the Genetic Mechanisms Cluster in the Molecular and Cellular Biosciences Division of the BIO Directorate. For the dsDNA case, single-particle experiments with bacteriophage lambda are designed to test the hypothesis that pressure-driven genome ejection can be completed by active processes like transcription by RNA polymerase. For the ssRNA case, a particular genus of simple plant virus, the well-characterized bromoviruses, is chosen as the model system. Experiments will be performed to measure the relative packaging efficiencies of a broad range of ssRNA molecules, viral, and non-viral, in order to discover the competing roles played by RNA charge, size, and shape. Further, to understand the evolutionary connection between these plant viruses and present-day mammalian counterparts such as the alphaviruses and flaviviruses, an attempt will be made to package these mammalian RNA genomes with plant capsid protein and to wrap the resulting nucleocapsids with phospholipid bilayer, in order to mimic enveloped viruses like dengue and hepatitis C.On a fundamental level, this research seeks to build a strong foundation for a physical understanding of viral infectivity. The emerging field of "Physical Virology" is contributing to the training of a new cadre of interdisciplinary science students and researchers who are equipped to apply fundamental ideas, approaches and techniques from chemistry and physics to basic biological problems like viral replication. Two new courses on general aspects of viruses have been taught to non-science undergraduate majors, and an outreach program has been developed for local high school students and teachers, exposing them to virus related research at UCLA and providing model-building and visualization projects for the classroom. In the longer term, this basic research may contribute to new approaches to anti-viral therapies based upon interference with the self-assembly of the ssRNA/capsid protein nucleocapsid and/or its wrapping by the lipid envelope.