BmNPV是蚕业生产中危害最严重的杆状病毒，其引起的损失约占蚕桑总产值的15%，目前为止尚无有效的治疗措施可以利用。我们的前期研究发现BmNPV入侵宿主细胞依赖于细胞膜上胆固醇，但具体作用机制尚不清楚，本研究将利用量子点示踪技术开展BmNPV与宿主之间的互作研究。首先确定病毒的胆固醇结合活性，对融合蛋白GP64中胆固醇识别序列进行点突变，通过突变病毒感染性的变化，确定有结合活性的胆固醇识别序列。其次探索病毒量子点标记条件、优化激光共聚焦显微镜示踪参数。最后开展病毒与宿主互作研究，确定胆固醇在病毒吸附等过程中的作用；利用激光共聚焦显微镜、流式细胞仪定性、定量分析标记病毒在不同剂量药物处理细胞中吸附、内化过程，并通过体内以及体外膜融合过程中荧光共定位及分离情况，明确胆固醇是否也参与膜融合，从而阐明胆固醇介导病毒入侵机制，为BmNPV防治研究及杆状病毒应用改良提供基础。

Bombyx mori nucleopolyhedrovirus (BmNPV) is the most severe baculovirus pathogen in sericultural industry, which caused about 15% loss of the total sericultural output value, and no treatment methods are currently available. Previous research showed that BmNPV entry into BmN cells depend on the cholesterol of the membrane in dose-dependent manner, the mechanism, however, need further investigation. In this study, the interaction between virus and host will be studied by quantum dot-labeled BmNPV. Firstly, the binding activity of cholesterol recognition amino acid consensus(CRAC) in GP64 will be clarified by recombinant viruses infectivity which possess point-mutant on the key amino acid of CRAC sequence. Secondly, exploring and optimizing the label condition and trafficking parameter on baculovirus which contained GP64 label by quantum dot and eGFP fused to VP39. Lastly, we will conduct the interaction analysis between virus and host cell. To confirm the role of cholesterol plays in the binding and internalization, the fluorescence intensity or percentage of the cells treated with/without different dose chemical were recorded by laser confocal microscope and flow cytometer. And to confirm whether cholesterol was involved in the subsequent membrane fusion, we will study the con-localization and separation of double fluorescence in vivo and in vitro. Therefore, the role of cholesterol plays in the infection will be illuminated, which will lay the foundation for the treatment research of BmNPV and baculovirus application and modification.