Hao Ruidong, He Jing, Liu Xing, Gao Guozhen, Liu Dan, Cui Lei, Yu Guojun, Yu Wenhui, Chen Yu, Guo Deyin
State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
Department of Molecular Carcinogenesis, the University of Texas MD Anderson Cancer Center, Smithville, Texas, USA.
J Virol. 2015 Apr;89(8):4345-55. doi: 10.1128/JVI.03094-14. Epub 2015 Feb 4.
Hepatitis B virus (HBV), a small enveloped DNA virus, chronically infects more than 350 million people worldwide and causes liver diseases from hepatitis to cirrhosis and liver cancer. Here, we report that hepatocyte nuclear factor 6 (HNF6), a liver-enriched transcription factor, can inhibit HBV gene expression and DNA replication. Overexpression of HNF6 inhibited, while knockdown of HNF6 expression enhanced, HBV gene expression and replication in hepatoma cells. Mechanistically, the SP2 promoter was inhibited by HNF6, which partly accounts for the inhibition on S mRNA. Detailed analysis showed that a cis element on the HBV genome (nucleotides [nt] 3009 to 3019) was responsible for the inhibition of the SP2 promoter by HNF6. Moreover, further analysis showed that HNF6 reduced viral pregenomic RNA (pgRNA) posttranscriptionally via accelerating the degradation of HBV pgRNA independent of La protein. Furthermore, by using truncated mutation experiments, we demonstrated that the N-terminal region of HNF6 was responsible for its inhibitory effects. Importantly, introduction of an HNF6 expression construct with the HBV genome into the mouse liver using hydrodynamic injection resulted in a significant reduction in viral gene expression and DNA replication. Overall, our data demonstrated that HNF6 is a novel host factor that can restrict HBV replication via both transcriptional and posttranscriptional mechanisms.
HBV is a major human pathogen whose replication is regulated by host factors. Liver-enriched transcription factors are critical for many liver functions, including metabolism, development, and cell proliferation, and some of them have been shown to regulate HBV gene expression or replication in different manners. In this study, we showed that HNF6 could inhibit the gene expression and DNA replication of HBV via both transcriptional and posttranscriptional mechanisms. As HNF6 is differentially expressed in men and women, the current results may suggest a role of HNF6 in the gender dimorphism of HBV infection.
乙型肝炎病毒（HBV）是一种小型包膜DNA病毒，全球慢性感染超过3.5亿人，可导致从肝炎到肝硬化和肝癌的肝脏疾病。在此，我们报告肝富集转录因子肝细胞核因子6（HNF6）可抑制HBV基因表达和DNA复制。HNF6的过表达抑制了肝癌细胞中HBV基因的表达和复制，而敲低HNF6表达则增强了HBV基因的表达和复制。机制上，HNF6抑制了SP2启动子，这部分解释了对S mRNA的抑制作用。详细分析表明，HBV基因组上的一个顺式元件（核苷酸[nt]3009至3019）是HNF6抑制SP2启动子的原因。此外，进一步分析表明，HNF6通过加速HBV pgRNA的降解在转录后降低病毒前基因组RNA（pgRNA），且不依赖La蛋白。此外，通过截短突变实验，我们证明HNF6的N端区域是其抑制作用的原因。重要的是，通过流体动力学注射将携带HBV基因组的HNF6表达构建体导入小鼠肝脏，导致病毒基因表达和DNA复制显著减少。总体而言，我们的数据表明HNF6是一种新型宿主因子，可通过转录和转录后机制限制HBV复制。
HBV是一种主要的人类病原体，其复制受宿主因子调控。肝富集转录因子对许多肝脏功能至关重要，包括代谢、发育和细胞增殖，其中一些已被证明以不同方式调节HBV基因表达或复制。在本研究中，我们表明HNF6可通过转录和转录后机制抑制HBV的基因表达和DNA复制。由于HNF6在男性和女性中差异表达，目前的结果可能提示HNF6在HBV感染的性别二态性中发挥作用。
