Messenger RNA Capping and Methylation in Pneumoviruses

描述(申请人提供)：副粘病毒是急性病毒性呼吸道感染的主要病原体。在副粘病毒中，人偏肺病毒(HMPV)、人呼吸道合胞病毒(RSV)和人副流感病毒3型(HPIV3)占急性病毒性呼吸道疾病的70%以上。尽管这些病毒造成了巨大的经济损失和精神负担，但目前还没有疫苗和抗病毒药物。副粘病毒信使RNA的5‘端含有独特的甲基化帽子结构，对病毒基因表达和随后的病毒复制是必不可少的。现有证据表明，副粘病毒mRNA帽结构的形成和甲基化与宿主不同。这种差异可能被用作疫苗开发和抗病毒疗法的目标。该项目将专注于hMPV，这是一种新发现的人类病原体，于2001年首次发现。本项目的目的是了解hMPV的mRNA封顶和甲基化的机制，并探索甲基转移酶作为hMPV新型疫苗开发的潜在靶点。我们的具体目标是：(1)确定hMPV的mRNA封顶机制；(2)确定hMPV的mRNA帽甲基转移酶的机制；(3)产生甲基转移酶缺陷的hMPV，并确定甲基转移酶缺陷病毒在细胞培养中是否减毒和遗传稳定；以及(4)确定甲基转移酶缺陷的hMPV在小鼠中是否减毒和遗传稳定，以及是否可以用作活疫苗候选。这些研究不仅将显著提高我们对病毒mRNA封顶和甲基化的理解，这是副粘病毒基因表达的关键步骤，而且还将填补我们在理解甲基转移酶在hMPV致病中的作用方面的一个重大空白，特别是我们对甲基转移酶缺陷的hMPV是否可以用作活疫苗候选的理解。从长远来看，我们的研究将通过靶向病毒mRNA帽的形成来促进新疫苗和抗病毒药物的合理设计。 公共卫生相关性：人类偏肺病毒(HMPV)是急性病毒性呼吸道感染的主要病原体之一。目前，还没有疫苗或抗病毒药物。本项目的目的是了解hMPV的mRNA封顶和甲基化的机制，探讨mRNA帽甲基化在病毒致病中的作用，并开发甲基转移酶缺陷病毒作为hMPV的活疫苗候选。

DESCRIPTION (provided by applicant): Paramyxoviruses are the leading causative agents of acute viral respiratory tract infections. Among the paramyxoviruses, human metapneumovirus (hMPV), human respiratory syncytial virus (RSV), and human parainfluenza virus type 3 (hPIV3) account for more than 70% of acute viral respiratory diseases. Despite the enormous economic losses and emotional burdens these viruses cause, vaccines and anti- viral drugs are currently not available. The 5' end of the messenger RNA (mRNA) of paramyxoviruses contains a unique methylated cap structure that is essential for viral gene expression and, subsequently, viral replication. Available evidence suggests that formation and methylation of the paramyxovirus mRNA cap structure differs from that of their hosts. This difference could potentially be used as a target for vaccine development and anti-viral therapies. This project will be focused on hMPV, a newly discovered human pathogen, first identified in 2001. The objective of this project is to understand the mechanism of mRNA capping and methylation in hMPV and to explore methyltransferase as a potential target for the development of novel vaccines against hMPV. Our specific aims are: (1) to define the mechanism of mRNA capping in hMPV; (2) to define the mechanism of mRNA cap methyltransferase in hMPV; (3) to generate methyltransferase -defective hMPV and to determine whether methyltransferase -defective viruses are attenuated and genetically stable in cell culture; and (4) to determine whether methyltransferase -defective hMPV is attenuated and genetically stable in mice and if it can be used as a live vaccine candidate. The proposed studies will not only significantly advance our understanding of viral mRNA capping and methylation, an essential step in paramyxovirus gene expression, but will also fill in a major gap in our understanding of the role of methyltransferase in hMPV pathogenesis, specifically, our understanding of whether methyltransferase-defective hMPV can be used as a live vaccine candidates. In the long-term, our research will facilitate the rational design of new vaccines and anti-viral drugs by targeting viral mRNA cap formation. PUBLIC HEALTH RELEVANCE: Human metapneumovirus (hMPV) is one of the leading causative agents of acute viral respiratory tract infections. Currently, there is no vaccine or anti-viral drug. The objective of this project is to understand the mechanism of mRNA capping and methylation in hMPV, to explore the role of mRNA cap methylation in viral pathogenesis, and to develop methyltransferase-defective viruses as a live vaccine candidates for hMPV.