Messenger RNA capping and methylation in pneumoviruses

摘要 这项申请是为了续签一项研究肺炎病毒RNA甲基化的拨款。肺炎病毒科是一种新病毒 家庭，于2016年通过将副粘病毒亚家族肺炎病毒提升到家庭地位而创建。这个 肺炎病毒科包括两种医学上重要的病原体，人类呼吸道合胞病毒(RSV)和 人类偏肺病毒(HMPV)，是急性病毒性呼吸道的主要病原体 婴儿、幼儿、老年人和免疫功能低下者的感染。尽管有巨大的 这些病毒造成的经济损失和精神负担，目前还没有疫苗或抗病毒药物可用。 开发这类制剂需要更好地了解其生命周期的所有方面。在最后一次拨款中 期间，我们揭示了肺炎病毒中mRNA封顶和帽甲基化的独特机制。我们 最近发现，肺炎病毒基因组、反基因组和mRNAs也在内部甲基化。 腺苷残基通过宿主M6A甲基转移酶复合体形成N6-甲基腺苷(M6A)。虽然M6A 20世纪70年代初，在病毒RNA中发现了甲基化，m6A在病毒生命周期中的生物学功能， 发病机制和免疫学四十年来一直是个谜。我们发现内部的M6A 病毒RNA的甲基化促进了肺炎病毒的复制和基因表达。当前的目标是 应用是确定内部m6A甲基化在肺炎病毒复制和发病机制中的作用 并确定M6A甲基化调控肺炎病毒生命周期的机制(S)。我们的特定 目标是：(1)定义宿主M6A机制，以调节肺炎病毒的复制和基因表达；(2) 确定体内M6A促进肺炎病毒复制和基因表达的机制(S)；以及 (3)探讨M6A甲基化在大鼠肺炎病毒复制和发病机制中的作用。这个 这项工作的成功完成不仅将促进我们对m6A甲基化在调控中的理解 肺炎病毒的生命周期和致病机制，也为研制活体减毒疫苗提供了新的途径 通过抑制病毒m6A甲基化的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.