Messenger RNA capping and methylation in pneumoviruses

摘要 这项申请是为了更新一项研究肺病毒RNA甲基化的资助。肺炎病毒科是一种新病毒 家族，于2016年通过将副粘病毒亚科肺炎病毒提升为家族地位而创建。的 肺炎病毒科包括两种医学上重要的病原体，人呼吸道合胞病毒（RSV）和 人偏肺病毒（human metapneumovirus，hMPV）是引起急性病毒性呼吸道感染的主要病原体 婴儿、幼儿、老年人和免疫功能低下个体的感染。尽管面临巨大 这些病毒造成的经济损失和情感负担，目前没有疫苗或抗病毒药物。 开发此类制剂需要更好地了解其生命周期的各个方面。在最后一次拨款中 在此期间，我们揭示了肺炎病毒中mRNA加帽和帽甲基化的独特机制。我们 最近发现，肺病毒基因组，反基因组和mRNA也在内部甲基化， 腺苷残基通过宿主m6 A甲基转移酶复合物形成N6-甲基腺苷（m6 A）。虽然m6 a 20世纪70年代初在病毒RNA中发现了甲基化，m6 A在病毒生命周期中的生物学功能， 发病机制和免疫力四十年来一直是个谜。我们发现，内部m6 A 病毒RNA中的甲基化促进肺病毒复制和基因表达。当前的目标 应用是确定内部m6 A甲基化在肺炎病毒复制和发病机制中的作用 在体内;以及确定m6 A甲基化调节肺病毒生命周期机制。我们的具体 目的是：（1）确定调节肺炎病毒复制和基因表达的宿主m6 A机制;（2） 确定内部m6 A促进肺病毒复制和基因表达的机制; (3)在棉鼠模型中确定m6 A甲基化在肺病毒复制和发病机制中的作用。的 这项工作的成功完成不仅将促进我们对m6 A甲基化在调节中的理解， 肺病毒的生命周期和发病机制，而且还提供了一种新的方法，用于开发活减毒 通过抑制病毒m6 A甲基化来制备候选疫苗和抗病毒药物。

Abstract This application is to renew a grant to study RNA methylation in pneumoviruses. Pneumoviridae is a new virus family, created in 2016 by elevating the paramyxoviral subfamily Pneumovirinae to family status. The Pneumoviridae family includes two medically important pathogens, human respiratory syncytial virus (RSV) and human metapneumovirus (hMPV), which are the leading causative agents of acute viral respiratory tract infections in infants, young children, the elderly, and immunocompromised individuals. Despite the enormous economic loss and emotional burden these viruses cause, no vaccines or anti-viral drugs are currently available. Development of such agents requires a better understanding of all aspects of their life cycle. In the last grant period, we have revealed the unique mechanism of mRNA capping and cap methylation in pneumoviruses. We recently discovered that pneumovirus genome, antigenome, and mRNAs are also methylated at internal adenosine residues to form N6-methyladenosine (m6A) by host m6A methyltransferase complex. Although m6A methylation has been discovered in viral RNA in early 1970s, the biological function of m6A in the virus life cycle, pathogenesis, and immunity has been a mystery for four decades. We have found that the internal m6A methylation in viral RNAs promotes pneumovirus replication and gene expression. The objectives of the current application are to determine the roles of internal m6A methylation in pneumovirus replication and pathogenesis in vivo; and to define mechanism(s) by which m6A methylation modulate pneumovirus life cycle. Our Specific Aims are: (1) to define the host m6A machinery that regulates pneumovirus replication and gene expression; (2) to define the mechanism(s) by which internal m6A promote pneumovirus replication and gene expression; and (3) to define the roles of m6A methylation in pneumovirus replication and pathogenesis in a cotton rat model. The successful completion of this work will not only advance our understanding of m6A methylation in regulating pneumovirus life cycle and pathogenesis, but also provide a novel approach for developing live attenuated vaccine candidates and antiviral drugs by inhibiting viral m6A methylation.