Structure and dynamics of RNA elements regulating viral aberrant RNA synthesis

总结 季节性流感病毒每年造成超过6亿例病例和数千亿美元的损失 损失。大流行性流感和禽流感病毒构成了更大的威胁， 我们的免疫反应失调和/或扩散到并关闭多个器官。电流 有证据表明，异常的病毒复制有助于先天性免疫缺陷的失调， 免疫应答和从低致病性菌株中出现高致病性菌株 前体 从低致病性病毒到高致病性病毒的转变涉及多个碱性氨基酸的插入， 病毒血凝素（HA）表面蛋白裂解位点的氨基酸。在鸟类中， HA允许病毒全身传播，导致家禽死亡率高达100%。 氨基酸在切割位点插入的分子机制尚不清楚 理解，但它可能涉及HA基因中RNA聚合酶的口吃，导致 核苷酸插入。 病毒RNA聚合酶还可以从病毒基因组中删除核苷酸，导致更短的核苷酸序列。 异常RNA最近的研究表明，大流行和禽流感A病毒感染 产生长度约为56-125个核苷酸的RNA分子，称为微型病毒RNA， 它们的合成与疾病标志物的上调相关。RNA聚合酶如何 在病毒基因组中造成如此大的缺失是未知的。 该项目将使用一种新的方法在病毒的关键步骤中阻止病毒RNA聚合酶。 复制和异常RNA合成，并使用最先进的生物化学，生物物理， 揭示病毒复制和基因组复制步骤的结构方法，以及 RNA合成异常在这样做的过程中，该项目将有助于一个完整的机械 了解流感复制，并回答长期存在的基本问题， 高致病性流感病毒的出现。

SUMMARY Seasonal influenza viruses cause >600 million cases annually and hundreds of billions of dollars in losses. Pandemic and avian influenza viruses present an even greater threat because they can dysregulate our immune response and/or spread to and shut down multiple organs. Current evidence suggests that aberrant viral replication contributes to a dysregulating of the innate immune response and the emergence of highly pathogenic strains from low pathogenic precursors. The transition from a low to highly pathogenic virus involves insertion of multiple basic amino acids in the cleavage site of the viral hemagglutinin (HA) surface protein. In birds, this change in HA allows the virus to spread systemically, resulting in mortality rates of up to 100% in poultry. The molecular mechanism underlying insertion of amino acids in the cleavage site is not well understood, but it may involve stuttering of the RNA polymerase in the HA gene, resulting in nucleotide insertions. The viral RNA polymerase can also delete nucleotides from the viral genome, resulting in shorter aberrant RNAs. Recent studies have shown that pandemic and avian influenza A virus infections produce RNA molecules of about 56-125 nucleotides in length, called mini viral RNAs, and that their synthesis is correlated with the upregulation of disease markers. How the RNA polymerase makes such large deletions in the viral genome is not known. This project will use a novel method to stall the viral RNA polymerase during key steps of viral replication and aberrant RNA synthesis, and use state-of-the-art biochemical, biophysical, and structural approaches to reveal the steps of viral replication and genome encapsidation, as well as aberrant RNA synthesis. In doing so, this project will contribute to a complete mechanistic understanding of influenza replication and answer long-standing, fundamental questions about the emergence of highly pathogenic influenza viruses.