MOLECULAR GENETIC ANALYSIS OF NDV PATHOGENESIS

病毒的致病机制是一个重要的问题。 我们计划基因，生化， 以纽卡斯尔病毒（NDV）为模型进行生物学研究 系统分析副粘病毒致病机理。 我们的工具包括Mandansky和Bratt的非细胞病变（nc）突变体， 温度敏感突变体和这些突变体的回复突变体;所有的 这些都是来自有毒和致细胞病变的澳大利亚-维多利亚 株（AV-WT），作为我们的主要将型病毒。 此外，本发明还提供了一种方法， 我们描述了各种不同类型的突变体及其回复突变体 来源于所选的一组天然存在的NDV毒株， 在毒力模式和许多相关的属性定义在 实验室 在适当的情况下，我们还将利用我们不断扩大的图书馆 NDV蛋白的单克隆抗体。 我们将继续探索与细胞致病性相关的表型， 毒力，希望确定我们以前的发现的普遍有效性 与AV-WT的nc突变体一起，其涉及mRNA调节的 细胞致病性和细胞间扩散。 我们将选择nc型突变体 来自另一种毒性和致细胞病变的NDV毒株， 无毒菌株的一些特征。 细胞间传播突变体 该菌株已被分离并将被鉴定。 第二 方法将涉及从无毒菌株中分离突变体：这些突变体将 包括噬斑形成突变体，在存在或不存在 外源蛋白酶和红细胞吸附阳性斑点形成突变体， 如先前对NC突变体所做的那样进行筛选。 我们将进一步探讨各种具体机制， 提示与细胞致病性或细胞杀伤有关。 可能 特定蛋白质的作用将通过使用well 已知的特征性TS突变体和中和抗性突变体 在膜糖蛋白的特定区域发生改变。 一个主要重点 将是探索这些糖蛋白在细胞中的可能作用， 杀人 我们还将探讨P蛋白在细胞间的作用， 传播. 最后，我们将测试一个假设，它调用了一个隔离的， NDV对总蛋白的抑制作用 合成.

Viral pathogenesis is an important problem. We plan genetic, biochemical, and biological studies using Newcastle disease virus (NDV) as a model system to analyze paramyxovirus pathogenesis. Our tools include the noncytopathic (nc) mutants of Mandansky and Bratt, temperature sensitive mutants, and revertants of these mutants; all of these are derived from the virulent and cytopathic Australia-Victoria strain (AV-WT) which serves as our principal will type virus. In addition, we describe a variety of different types of mutants and their revertants derived from a selected panel of naturally occurring NDV strains differing in virulence patterns and numerous related properties definable in the laboratory. Where appropriate, we will also employ our expanding library of monoclonal antibodies to NDV proteins. We will continue to explore phenotypes relevant to cytopathogenicity and virulence, hoping to determine the general validity of our previous finding with the nc mutants of AV-WT which have implicated both mRNA modulated cytopathogenicity and cell to cell spread. We will select nc type mutants from another virulent and cytopathic NDV strain which already possesses some characteristics of avirulent strains. Cell to cell spread mutants of this strain have been isolated and will be characterized. A second approach will involve isolating mutants from avirulent strains: these will include plaque forming mutants, screened for in the presence or absence of exogenous protease, and hemadsorption positive spot forming mutants, screened for as previously done for the nc mutants. We will further explore a variety of specific mechanisms which have been suggested to be involved in cytopathogenicity or cell killing. Possible roles of specific proteins will be explored through the use of well characterized ts mutants and neutralization resistant mutants known to be altered in specific regions of the membrane glycoproteins. A major focus will be the exploration of possible roles of these glycoproteins in cell killing. We will also explore the role of the P protein in cell to cell spread. Finally, we will test an hypothesis which invokes a sequestering of ribosomes by non-translatable mRNA in NDV's inhibition of total protein synthesis.