宿主DEAD-BOX RNA解旋酶DDX5和DDX17抑制乙肝病毒复制的作用及机制研究

慢性HBV 感染患者肝细胞调控HBV 复制的机制目前仍未阐明。我们前期研究采用Affymetrix RNA芯片，首次发现慢乙肝患者肝组织内RNA解螺旋酶DDX5/17的表达水平和HBV复制均呈明显负相关；进一步在肝细胞内行共转染实验，发现DDX5/17基因对HBV RNA没有作用，但能够明显地抑制包裹了核衣壳的HBV pgRNA。既往研究提示：DDX17可强烈结合于茎环结构，然后转移至胞浆发挥抗病毒作用。我们推测，DDX5/DDX17可能在胞核中与HBV Pg RNA的茎环结构ε结合，然后转移至胞浆通过影响pgRNA与聚合酶、核心蛋白形成pg RNA-蛋白质复合体（解螺旋作用）而抑制HBV复制。本课题拟在肝癌细胞系体外模型和高压尾静脉注射的小鼠模型中研究DDX5/DDX17抑制HBV复制的作用机制。本研究有助于阐明新的宿主基因调控HBV 复制的机制，为寻找抗HBV 的新靶位提供理论依据。

The exact role of how host genes in liver regulate hepatitis B virus replication is still unknown. Our previous study showed that the intraheptic DDX5/DDX17 gene expression levels were negatively correlated with patients’ serum HBV-DNA titers. In vitro cotransfection experient showed that both DDX5 and DDX17 could inhibit HBV replication in HepG2 cells. Interestingly, HBV RNA remained unchanged, while encapsidated pgRNA decreased. It was reported that DDX17 may recognize stem-loop structure to inhibit other virus replication. We propose DDX5/DDX17 may translocate to cytoplasma to inhibit pg RNA encapsidation through binding to HBV stem-loop structure ε.To validate this hypothesis, transient infection, knock-out HBV stable cellline, NCTP-HepG2 infection system and hydrodynamic infection mice were all employed. This study will help to identify the novel mechanism of intrinsic host antiviral factor with activity against HBV.