HOST-VIRUS INTERACTION AND GENE EXPRESSION

这项提议的长期目标是理解分子 呼吸道病原体--人副流感的致病性基础 病毒3(HPIV3)，副粘病毒科的成员。副流感 病毒是仅次于呼吸道的重要呼吸道病原体 合胞病毒，作为儿童常见疾病的病原体，如 鼻炎、咽炎和支气管炎。在不同地区的研究 世界表明，这些病毒与大约40%的 儿童患有严重的咽喉炎。在其他HPIV中，HPIV3致病性最强 类型。到目前为止，控制儿童感染的有效疫苗已经 这是不够的。 尽管有大量关于结构和 HPIV3基因组的核苷酸序列是已知的，我们对 这种重要的人类病原体的基因表达机制微乎其微。 为了深入了解病毒基因的功能，我们 最近开发了一种HPIV3的体外转录系统， 在体外有效地合成病毒特异性的mRNAs。更重要的是， 我们证明了细胞肌动蛋白是有效转录所必需的。 在体外发生，提示可能参与了细胞骨架 网络在HPIV复制的生命周期中。为了勾勒出这个机制 HPIV3基因表达及细胞骨架作用的研究 蛋白质(S)在这个过程中，我们建议详细研究其作用 HPIV3中的细胞肌动蛋白及其结合蛋白 病毒RNA的转录/复制及其功能作用 聚合酶蛋白(L蛋白和P蛋白)在这些过程中。 将进行深入研究，以确定分子形式 转录所需的肌动蛋白以及是否有任何其他细胞蛋白， 例如肌动蛋白结合蛋白，是肌动蛋白发挥功能所必需的。在……里面 肌动蛋白在RNA合成和结合中的作用方式 肌动蛋白与病毒核衣壳的体外和体内研究。这个 病毒核糖核酸聚合酶组分(L蛋白和P蛋白)的功能 转录和复制及其与细胞肌动蛋白的相互作用 将会被研究。重点将放在病毒P基因上，它编码 除了P蛋白、C蛋白和P-D蛋白，后一种蛋白 由一种新的编辑机制产生。了解这些组件的功能 蛋白质与P基因转录过程中独特的编辑反应 与肌动蛋白在这些过程中的作用肯定会提供更深层次的 HPIV3和HPIV3-细胞基因表达机制的研究 蛋白质的相互作用。

The long term goal of the present proposal is to understand the molecular basis of pathogenicity of the respiratory pathogen, human parainfluenza virus 3 (HPIV3), a member of the family paramyxoviridae. The parainfluenza viruses are important respiratory tract pathogens, second to respiratory syncytial virus, as causative agents of common illnesses of children like rhinitis, pharyngitis, and bronchitis. Studies in different parts of the world indicate that these viruses are associated with approximately 40% of severe croup in children. HPIV3 is most pathogenic among the other HPIV types. Effective vaccines to control infection in children have so far been inadequate. Although considerable information regarding the structure and the nucleotide sequence of the genome of HPIV3 is known, our knowledge of the mechanism of gene expression of this important human pathogen is meager. To gain insight into understanding the functions of the viral genes, we recently developed an in vitro transcription system for HPIV3 which efficiently synthesizes virus-specific mRNAs in vitro. More importantly, we demonstrated that cellular actin was needed for effective transcription in vitro to occur, suggesting a possible involvement of cytoskeletal network in the life-cycle of HPIV replication. To delineate the mechanism of gene expression of HPIV3 and study the role of cellular cytoskeletal protein(s) in this process, we propose to study in detail the role of cellular actin and actin-binding proteins in HPIV3 transcription/replication as well as the functional roles of viral RNA polymerase proteins (L and P proteins) in these processes. An in-depth study would be carried out to determine the molecular form of actin required for transcription and whether any other cellular proteins, e.g. actin-binding proteins, are necessary for actin to function. In addition, mode of action of actin in RNA synthesis as well as association of actin with viral nucleocapsid in vitro and in vivo will be studied. The functions of viral RNA polymerase components (L and P proteins) in transcription and replication and their interaction with cellular actin will be studied. Emphasis would be laid on the viral P gene which encodes, in addition to the P protein, C protein and P-D protein, the latter protein arising by a novel editing mechanism. Understanding the functions of these proteins and the unique editing reaction during P gene transcription along with the role of actin in these processes would certainly provide deeper insight into the mechanism of gene expression of HPIV3 and HPIV3-cell protein interactions.