RNA结合蛋白RBM24通过ε元件调控HBV pgRNA翻译和逆转录的分子机制

乙肝病毒（HBV）是引起慢性肝炎的重要病原体。其前基因组RNA （pgRNA）作为关键的复制中间体，承担着翻译模板和逆转录模板的双重功能，但其间的调控机制尚不清晰。前期研究提示RNA结合蛋白RBM24与pgRNA的关键元件ε结合负调控pgRNA翻译、但正调控pgRNA逆转录，可能是一个全新的pgRNA功能调控蛋白。本项目拟通过具体分析RBM24对核糖体在ε元件上组装的影响，及RBM24-ε结合的关键结构域在其中的功能，阐释RBM24负调控pgRNA翻译的机制；通过分析RBM24对pgRNA包装、蛋白引发及逆转录成负链DNA的影响，及RBM24-ε-Pol互作的关键结构域在其中所起的作用，解析RBM24正调控pgRNA逆转录的环节和机制；进而揭示RBM24对pgRNA翻译—逆转录的动态调控机理。研究结果有望揭示新型宿主因子调控HBV翻译及复制的分子新机制，为抗HBV新药的研发提供全新的线索。

Hepatitis B virus (HBV) is one of the most important pathogens which can cause chronic hepatitis. HBV pregenomic RNA (pgRNA) plays essential roles during virus replication, which acts either as mRNA for translation or as a template for reverse transcription. However, it remains unclear how pgRNA translation and reverse transcription are coordinated. Our preliminary data has shown that RBM24, one of RNA binding proteins, binds to ε, the essential element of pgRNA to negatively regulate pgRNA translation while positively regulate pgRNA reverse transcription. Therefore, RBM24 may be a novel host factor to orchest the function of pgRNA. In the present project, the impact of RBM24 on the ribosome assembly on ε element will be analyzed. Moreover, the key domains in deciding RBM24-ε binding will be identified and their role in the ribosome assembly will be clarified to reveal the mechanism by which RBM24 negatively modulates pgRNA translation. The influence of RBM24 on pgRNA encapsidation, protein priming and reverse transcription into minus strand DNA will be investigated to clarify the step by which RBM24 positively regulates pgRNA reverse transcription. The key domains mediating RBM24-ε-Pol interaction will be identified and their role in pgRNA reverse transcription will be analyzed to uncover the mechanism by which RBM24 positively regulates pgRNA reverse transcription. Furthermore, it will also be revealed that the mechanism by which RBM24 modulates switch of pgRNA from translation to reverse transcription. Taken together, this project could not only shed light on the new molecular mechanism by which host factors ochest HBV translation and replication, but also provide new clues for antiviral drug screening.