乙型肝炎大表面抗原LHBs是病毒S基因编码的完整蛋白，与病毒组装、释放等过程密切相关；近年来发现其与另一个病毒编码蛋白HBx一样，也是在乙型肝炎发生、发展过程中起重要作用的转录激活蛋白。申请者一直致力于LHBs相关功能的研究。我们在前期工作中首次发现LHBs与缺氧诱导因子HIF1存在相互作用；并且在HBV复制细胞系中敲除HIF1，能显著影响病毒复制水平。那么，两者的相互作用对HBV复制及乙型肝炎的发生、发展有何作用？这些作用具体又是如何实现的？本项目拟采用定量免疫共沉淀结合小干扰RNA技术研究蛋白质相互作用谱（“QUICK”）的方法，在HBV复制细胞系中分离、鉴定出与HIF1存在相互作用的蛋白分子；并通过生物信息学方法，绘制出HIF1在慢性HBV感染中的相互作用分子网络，以探讨LHBs调控HIF1表达的机制、HIF1参与HBV复制及乙型肝炎发生发展过程的确切机制。

Hepatitis B virus large surface protein (LHBs) is a complete S protein transcribed and translated by S gene, which has many cellular functions, and is an important factor in the process of chronic HBV infection. In our previous work, hypoxia induced factor 1 (HIF1) was identified to be interacted with LHBs. And the level of HBV DNA decreased significantly after down-regulating the expression of HIF1 in HepG2.2.15. However, what is the relationship between HIF1 and LHBs and how does it affect the development of chronic hepatitis B? In current case, the interaction between HIF1 and LHBs will be further confirmed by immunoprecipitation and GST pull-down assays in vivo and in vitro. In addition, we will perform a systematic proteomic analysis of HIF1-associated proteins in HepG2.2.15 cells to gain a better insight into the molecular mechanism of HIF1 in chronic HBV infection. A new developed technique called QUICK (quantitative immunoprecipitation combined with knockdown), which integrated immunoprecipitation, RNAi, iTRAQ and quantitative Mass technologies, will help a lot in the whole process. After using this system coupled with bioinformatics, a protein interaction map of HIF1 will be generated, and the molecular regulatory mechanism from LHBs to HIF1 will be revealed. These data would be valuable for further study of the mechanism of chronic HBV infection, and also provide some new clues for curing chronic HBV infection.