草莓镶脉病毒致病因子P6蛋白与草莓抗病相关锌指蛋白ZFP的互作机制研究

Strawberry vein banding virus (SVBV) belongs to genus Caulimovirus, family Caulimoviridae. It was demonstrated in our research that protein P6 of SVBV is a RNA silencing suppressor and a symptom determinant which closely related to the virus pathogenicity. However, it has not been reported that how protein P6 interacts with host factor influence virus pathogenicity. The cDNA library of the Fragaria vesca was constructed in our research, and protein P6 was used as a bait to screen out a host factor Zinc finger protein ZFP which interacts with P6. Zinc finger protein ZFP plays an important role in plant growth and development, stress resistance and disease resistance, and it is likely to be an extremely important host factor regulating the functions of P6. In this project, the P6 and ZFP subcellular localization and their co-localization were firstly analyzed and the interaction domain of the two proteins was analyzed as well. On the basis of determining interaction of P6 with ZFP, it was illustrated that the interaction had the effect on pathogenic action of SVBV. Furthermore, binding capacity of ZFP-P6 complex and SVBV 35S RNA was explored. Finally, it was clarified that interaction of P6 with ZFP had interference effect on replication process of SVBV. This study has great significance in revealing the molecular mechanism of the interaction of SVBV P6 with strawberry ZFP and the defense and counter-defense mechanism between host plant and DNA virus.

草莓镶脉病毒（SVBV）属于花椰菜花叶病毒属，本课题组已证明SVBV P6蛋白是一个沉默抑制子和症状决定子，与病毒的致病性密切相关，但P6如何与寄主因子互作影响病毒的致病性尚未见报道。本课题组构建草莓cDNA文库，以P6蛋白为诱饵筛选出与其互作的寄主因子锌指蛋白ZFP。锌指蛋白ZFP在植物生长发育、抗逆和抗病等方面具有重要作用，可能是调控P6蛋白功能的重要寄主因子。本项目首先分析P6蛋白和ZFP蛋白的亚细胞定位和共定位情况以及二者的互作功能域。在确定P6蛋白和ZFP蛋白互作的基础上，探明ZFP蛋白与P6蛋白互作对SVBV致病作用的影响，再进一步探究ZFP-P6复合体与SVBV 35S RNA的结合能力，最终解析ZFP与P6互作对SVBV复制进程的干涉作用。本研究的开展对揭示SVBV P6蛋白与草莓锌指蛋白ZFP互作分子机制以及寄主植物和双链DNA病毒之间防御和反防御机理均具有重要意义。

草莓镶脉病毒（SVBV）属于花椰菜花叶病毒属，本课题组已证明SVBV编码的P6蛋白是病毒的沉默抑制子和症状决定子，影响病毒的致病性，但尚未有研究报道P6蛋白如何与寄主因子互作影响病毒的致病性。本课题组构建草莓cDNA文库，以P6蛋白为诱饵筛选出与其互作的寄主因子锌指蛋白ZFP。锌指蛋白ZFP在植物生长发育、抗逆和抗病等方面具有重要作用，可能是调控P6蛋白功能的重要寄主因子。本研究证明了P6蛋白和ZFP蛋白的亚细胞定位和共定位情况以及二者的互作功能域， ZFP蛋白能够利用泛素化途径降解P6蛋白，探明了ZFP蛋白与P6蛋白互作对SVBV致病作用的影响。进一步探究发现ZFP蛋白能够结合SVBV 35S启动子，最终解析了ZFP与P6互作对SVBV复制进程的干涉作用。本研究的开展对揭示SVBV P6蛋白与草莓锌指蛋白ZFP互作分子机制以及寄主植物和双链DNA病毒之间防御和反防御机理均具有重要意义。