草鱼呼肠孤病毒（Grass carp reovirus,GCRV）是草鱼出血病的致病病原。前期研究发现：GCRV-873类型病毒的最外层衣壳蛋白VP7、GCRV-HZ08类型病毒的纤突蛋白VP56和GCRV-104类型病毒的纤突蛋白VP55 均与草鱼胞外基质蛋白Fibulin-4在酵母内相互作用。本项目拟利用基因突变体构建与表达、体外蛋白质结合实验、免疫组织化学分析、Fibulin-4的阻断剂竞争抑制实验等方法进一步确证Fibulin-4与3种基因型GCRV最外层衣壳蛋白在体、内外的相互作用及其效应。项目的研究结果将明确Fibulin-4 在GCRV组织嗜性中的作用机制, 并有利于阐明临床上红肠、红肌肉和红鳃盖三种典型草鱼出血病症状出现的分子病理学基础; 解析三种基因型GCRV病毒最外层衣壳蛋白与同一种胞外基质蛋白Fibulin-4的相互作用，也能从药物构效关系上指导合成广谱抗病毒药物。

Grass carp reovirus is the causing pathogen for grass carp hemorrhagic disease. In the pilot study of this project, the outermost capsid protein VP7 of GCRV-873, VP56 of GCRV-HZ08, and VP55 of GCRV-104 interacted with grass carp extracellular protein Fibulin-4 in yeast-two hybrid screen. Here，different methods will be applied to study the in vitro and in vivo interactions between Fibulin-4 and each of the viral outer capsid proteins, which include gene mutagenesis and expression, protein binding in vitro, immunohistochemistry and small ligands-mediated binding inhibition tests. The results should contribute for clarifying the role of Fibulin-4 in tissue tropism of all genotypes of grass carp reoviruses, and be helpful in understanding the clinical symptoms of GCRV infection that demonstrate bleeding in muscle, opercular and intestine.Characterization of the interactions between Fibulin-4 and outermost capsid proteins of all the three genotypes of GCRV paves the way for designing broad-spectrum antiviral drug from the structure-activity relationships.