Mechanism of VEE Attenuation

VEE衰减机制

• 批准号: 6340215
• 负责人: LAURA J WHITE
• 金额: $ 4.2万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6340215
• 关键词: Venezuelan equine encephalitis virus; attenuated microorganism; gene mutation; host organism interaction; interferons; laboratory mouse; virulence; virus genetics

DESCRIPTION: (Adapted from the Investigator's abstract): Venezuelan equine encephalitis virus (VEE) is an important equine and human pathogen. It periodically emerges in epidemics caused by highly virulent epizootic strains. Virulence determinants of the natural VEE strains are not well understood at the molecular level. In vaccine strains and laboratory attenuated strains, virulence determinants for mice have been mapped to El and E2 glycoproteins and the 5' untranslated region (utr). A single change at nucleotide 3 (nt3) of the 5' utr of the VEE genome (G to A substitution) introduced into a molecular clone of wild-type virulent VEE results in a virus that is completely attenuated in mice. The long-term goal is to determine the mechanisms by which specific mutations in the 5' utr of the VEE genome attenuates the virus, and to use the VEE system to elucidate the role of lFNAB in alphaviruses pathogenesis. We hypothesize that the nt3A mutation results in a virus with increased sensitivity to the antiviral actions of lFNaB due to increased levels of viral dsRNA replication intermediates, consequently (a) increasing induction of IFN-stimulated antiviral genes, (b) enhancing activation of IFN-induced antiviral proteins that require dsRNA as cofactor, or alternatively, (C) the nt3A mutant virus may be slower in inhibiting host protein synthesis, allowing continued synthesis of key antiviral activities. We will test these hypotheses in the context of the following specific questions: 1) What is the relative contribution of INFaB-induced antiviral pathways PKR and 2'-5' OAS/RNase L in the inhibition of replication of wild type compared to nt3A mutant VEE in vitro and in vivo? 2) Does the nt3A mutation affect the induction and/or the activation of downstream IFNaB effector mechanisms such as PKR, 2'-5' OAS, RNase L, and ADAR? and 3) What is the effectof the nt3A mutation on virus-induced host protein synthesis inhibition?

描述：（改编自研究者的摘要）：委内瑞拉马 脑炎病毒（VEE）是一种重要的马和人类病原体。它 周期性地出现在由高毒力动物流行菌株引起的流行病中。 天然 VEE 菌株的毒力决定因素尚未得到充分了解 分子水平。在疫苗株和实验室减毒株中， 小鼠的毒力决定簇已被定位到E1和E2糖蛋白，并且 5'非翻译区（utr）。核苷酸 3 (nt3) 处的单个变化 VEE 基因组的 5' utr（G 至 A 替换）引入分子 野生型强毒VEE的克隆产生了完全被破坏的病毒 在小鼠中减弱。长期目标是确定机制 VEE 基因组 5'utr 中的特定突变可减弱病毒，并 使用 VEE 系统阐明 lFNAB 在甲病毒发病机制中的作用。 我们假设 nt3A 突变导致病毒的病毒数量增加 由于病毒水平增加而对 lfNaB 的抗病毒作用敏感 dsRNA 复制中间体，因此 (a) 增加诱导 IFN 刺激的抗病毒基因，(b) 增强 IFN 诱导的激活 需要 dsRNA 作为辅因子的抗病毒蛋白，或者 (C) nt3A突变病毒抑制宿主蛋白质合成的速度可能较慢，从而允许 持续合成关键的抗病毒活性。我们将测试这些假设 在以下具体问题的背景下： 1）什么是相对的 INFaB 诱导的抗病毒途径 PKR 和 2'-5' OAS/RNase L 的贡献 与nt3A突变体VEE相比，野生型体外复制的抑制 以及体内？ 2) nt3A突变是否影响诱导和/或 激活下游 IFNaB 效应机制，例如 PKR、2'-5' OAS、 RNase L 和 ADAR？ 3) nt3A 突变对 病毒诱导宿主蛋白合成抑制？