HOST RANGE DETERMINANTS OF INFLUENZA VIRUS

长期目标是这项研究是为了理解分子 允许新的致病病毒在中国出现的机制(S) 人类，以甲型流感病毒为模型。在过去的三十年里， 几种新的病毒病原体在人类身上出现后，在 人类种群较少或在其他动物宿主中。大流行性流感 菌株是后者的典型例子；血凝素(HA)， 1957年和1968年大流行毒株的神经氨酸酶(NA)和PbI基因 都来自禽流感病毒。之前的研究已经 大流行性流感甲型流感和甲型流感的基因变化 改变这些病毒宿主范围的菌株，尽管 这种影响的结构基础尚不清楚。这项建议旨在 确定甲型流感病毒宿主范围的分子基础 限制。反向遗传学技术的最新进展 Palese和他的同事，结合三人提供的信息- HA和NA的空间结构，现在允许直接检查 特定氨基酸变化与寄主范围的相关性 甲型流感病毒。提出了以下具体目标：1. 阐明决定宿主的HA的结构特征 甲型流感病毒的范围特异性。人体内氨基酸的变化 禽流感病毒HA是有效复制病毒所必需的 松鼠猴子将被识别，与它的受体有关 特异性，通过使用反向遗传学产生流感病毒 在HA中含有特定的突变。2.确定 影响流感宿主范围的NA的分子特征 一种病毒。NA底物专一性的结构基础 将通过体外诱变来建立。对中国经济的影响 病毒寄主范围限制的底物专一性 然后在鸟类和哺乳动物系统中通过引入 NA中的特定突变，使用反向遗传学。了解以下内容 高效的禽流感病毒HA和NA所需的氨基酸变化 哺乳动物的复制应该可以让我们评估鸟类的潜力- 就像非人类哺乳动物中的病毒一样，为后代提供基因 大流行毒株，使预测(和可能)成为可能 预防)未来的人类流感大流行。它也可以应用于 导致人类流感病毒减毒的产生 活疫苗毒株。FINE受体的鉴定和 HA和NA的底物特异性应提供基本信息 需要设计抗病毒药物来抑制这种活性 在不影响细胞过程的情况下，这些病毒成分。

The long-term goal is this research is to understand the molecular mechanism(s) permitting the emergence of new pathogenic viruses in humans, using influenza A viruses as a model. In the last three decades, several new viral pathogens appeared in humans after being maintained in small human populations or in other animal hosts. Pandemic influenza strains are classic examples of the latter type; the hemagglutinin (HA), neuraminidase (NA), and PBI genes of the 1957 and 1968 pandemic strains were derived from avian influenza viruses. Previous studies have demonstrated genetic changes in both the HA and NA of pandemic influenza strains that altered the host range of these viruses, although the structural basis of such effects are unknown. This proposal seeks to determine the molecular basis of influenza A virus host range restriction. Recent development of the reverse genetics techniques by Palese and colleagues, combined with information provided by the three- dimensional structures of the HA and NA, now permits direct examination of the relevance of specific amino acid alterations to the host range of influenza A viruses. The following specific aims are proposed: 1. Elucidation of the structural features of the HA that determine the host range specificity of influenza A viruses. Amino acid changes in the avian virus HA required for efficient replication of the virus in squirrel monkeys will be identified, in relation to its receptor specificity, by using reverse genetics to generate influenza viruses containing specific mutations in the HA. 2. Determination of the molecular features of the NA that influence the host range of influenza A viruses. The structural basis of the substrate specificity of the NA will be established by in vitro mutagenesis. The influence of the substrates specificity on the host range restriction of the virus will then be determined in both avian and mammalian systems by introducing specific mutations in the NA, using reverse genetics. Knowledge of the amino acid changes in the avian virus HA and NA required for efficient replication in mammals should allow us to assess the potential of avian- like viruses in nonhuman mammals to provide the genes for the generation of the pandemic strains, making it possible to predict (and possible prevent) future pandemic of human influenza. It could be also applied to the attenuation of human influenza viruses leading to the generation of live vaccine strains. Identification of the fine receptor and substrate specificities of the HA and NA should provide basic information needed for designing antiviral agents that would inhibit the activities of these viral constituents without affecting cellular processes.