猪圆环病毒2型（PCV2）ORF1编码复制酶相关蛋白（Rep和Rep'蛋白），是病毒复制所必需的；ORF2编码的Cap蛋白是构成病毒衣壳的唯一结构蛋白。研究表明PCV2 Cap与Rep蛋白存在相互作用，但这两种蛋白在病毒复制过程中相互作用的分子机制尚不清楚。为了阐明Cap和Rep蛋白相互作用及其在PCV2组装过程中的功能，本研究以PCV2感染PK-15细胞及猪T淋巴细胞，采用定量共定位分析和免疫共沉淀技术追踪这两种蛋白相互作用的动态发展；再通过截短表达和定点突变技术对Cap和Rep相互作用的关键位点进行鉴定；采用感染性克隆技术拯救Cap和Rep相互作用缺陷的突变毒株，进而分析这些毒株的基因组复制、蛋白表达、病毒组装及繁殖能力，旨在阐明Cap和Rep相互作用在病毒组装过程中的功能。预期结果为PCV2组装机制与病毒复制机理提供新的科学理论。

Porcine circovirus type 2 (PCV2) ORF1 encodes the non-structural replication proteins, Rep and Rep', which are both necessary for viral replication. PCV2 ORF2 is translated into the capsid protein (Cap), which is the unique structure protein and make up the icosahedral capsid protecting the viral genome. It has been demonstrated before that Rep interacts with Cap. However, it is not known that the fuction of the interaction between Cap and Rep during the PCV2 replication cycle. In order to investigate its kinetic characteristic, interactional sites and function during PCV2 assembly, the PK-15 cells and porcine T lymphocytes will be infected by PCV2 respectively, and then the kinetic characteristic of Cap-Rep interaction will be analyzed using quantitative colocalization analysis of confocal fluorescence microscopy images and co-immunoprecipitation.The crucial binding sites of Cap-Rep interaction will be mapped by the truncation expression and the site-directed mutagenesis. PCV2 mutants with Cap-Rep interaction defect will be constructed and rescued, and then their characteristc containing genome replication, protein expression, virus assembly and propagation will be investigated. This study will enrich the knowledge on the Cap-Rep interaction during PCV2 assembly and provide new scentific information on PCV2 replication mechanism.