中文摘要：

目的观察细胞质内的DNA依赖的干扰素调节因子激活物（DAI）对HBV复制的影响，并初步探讨其影响机制。方法首先将siDAI与HBV1．3复制型质粒pHYl06共转染HepG2细胞，实验分两组：一组转染后6h，提取细胞总RNA，实时定量RT—PCR检测细胞内干扰素诱导的含三角形四肽重复蛋白（IFIT）1与白细胞介素6的表达水平。另一组在转染后第4天收集细胞上清液，酶联免疫吸附法检测HBsAg与HBeAg的表达水平；抽提细胞内的HBV核心颗粒，Southernblot检测细胞内HBV复制中间体（松弛环状DNA、双链线性DNA、单链DNA）。然后将siDAI、siTBK与HBV1．3复制型质粒DHY106共转染HeDG2细胞，同样方法检测转染后细胞上清液中HBsAg和HBeAg的表达。两组间均数比较采用独立样本t检验，多组问比较采用方差分析。结果siDAI转染导致了胞内DAI表达下调；DAI表达水平下降后HBV的复制与病毒蛋白表达受到了抑制：HBsAg和HBeAg的相对表达水平在siDAI组分别为0．0195±0．0050、0．0140±0．0040，在空白对照组为0．3150±0．0200、0．0124±0．0135，差异有统计学意义（t=14．770，P〈0．05；f=7．777，P〈0．05）；且抑制效果呈剂量依赖性。下调DAI后，对HBV诱导的IFIT1、白细胞介素6表达没有影响垆〉0．05）。同时下调DAI和TBKl后，HBV蛋白表达仍然受到抑制。结论下调DAI能抑制HBV的复制与蛋白表达，其机制与I型干扰素及核因子-kB信号通路无关。

英文摘要：

Objective To explore the effect of the cytoplasmic DNA sensor DM on replication of hepatitis B virus （HBV） and its possible mechanism. Methods The bepatocyte-derived cell line HepG2 was co-transfected with DAI siRNA and the HBV1.3 replicative plasmid PHY106, and the cells were divided into two experimental groups. Six hours later, total RNA was extracted from the first group of cells and expression of IFIT1 and IL-6 were detected by real-time RT-PCR. The second group of cells was incubated for 4 days, after which the cell supematant was collected and the HBV surface antigen （HBsAg） and envelope antigen （HBeAg） were detected by ELISA. In addition, HBV core particles were extracted and applied to southern blot assay to detect the intracellular H13V replication intermediates （rcDNA, dlDNA and ssDNA）. Next, the HepG2 cells were triple transfected with siRNA targeting the type I interferon pathway molecule TBK1 and DM simultaneously and HI3V1.3, after which HBV viral proteins were detected. Two-group comparisces were made using the independent sample t-test, and more- than-2-group comparisons were made using ANOVA. Results DAI gene expression was down-regulated in response to DM siRNA transfection. Cells with down-regulated DAI showed inhibited HBV replication （in a dosedependent manner）, accompanied by reduced levels of HBsAg （0.0195±0.0050 vs. control： 0.3150±0.0200, P 〈 0.05, t = 14.77） and HBeAg （0.0140±0.0040 vs. control： 0.01235±0.0135,P 〈 0.05, t = 7.777）. No effect of down- regulated DAI was observed for the expression of IFIT1 of IL-6. siRNA-mediated down-regulation of TBK1 and DAI simultaneously led to reduced expression of HBsAg and HBeAg. Conclusion Down-regulation ofDAI gene expression inhibited HBV replication and HBV protein expression, but the underlying mechanism was not related to the type I interferon or NF-rd3 signaling pathway.