Hepatitis B virus X protein is essential to initiate and maintain virus replication after infection
Hepatitis B virus X protein is essential to initiate and maintain virus replication after infection
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DOI：
10.1016/j.jhep.2011.02.015
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发表时间：
2011-11-01
影响因子：
25.7
通讯作者：
Protzer, Ulrike
中科院分区：
文献类型：
--
作者：
Lucifora, Julie;Arzberger, Silke;Protzer, Ulrike
背景与目的：乙型肝炎病毒（HBV）的分子生物学已经得到了广泛的研究，但乙型肝炎X蛋白（HBx）在自然HBV感染中的确切作用仍然未知。方法：用野生型（HBV(wt)）或HBx缺陷型（HBV(x-)） HBV颗粒感染原代人肝细胞和允许HBx条件反式互补的分化HepaRG细胞，建立HBV复制。结果：我们观察到，与接种野生型HBV颗粒（HBV(wt)）的细胞相反，接种hbx缺陷HBV颗粒（HBV(x-)）的细胞不会导致生产性HBV感染。虽然相同数量的核共价闭合环状HBV- dna （cccDNA）显示出相当的摄取和核输入，但仅在HBV（wt）基因组中观察到主动转录。HBx的反式互补能够挽救HBV（x-）基因组的转录，并导致抗原和病毒粒子的分泌，甚至在感染后数周。HBx的持续表达是维持HBV抗原表达和复制所必需的。最后，我们证明了HBx在组装过程中不被包装成病毒粒子，而是在感染后在新宿主细胞内表达，从而允许cccDNA对HBV转录进行表观遗传控制。结论：我们的研究结果表明HBx是启动和维持HBV复制所必需的，并强调HBx在自然感染过程中是关键的调节因子。(C) 2011年欧洲肝脏研究协会。Elsevier B.V.版权所有。
Background & Aims: The molecular biology of hepatitis B virus (HBV) has been extensively studied but the exact role of the hepatitis B X protein (HBx) in the context of natural HBV infections remains unknown.Methods: Primary human hepatocytes and differentiated HepaRG cells allowing conditional trans complementation of HBx were infected with wild type (HBV(wt)) or HBx deficient (HBV(x-)) HBV particles and establishment of HBV replication was followed.Results: We observed that cells inoculated with HBx-deficient HBV particles (HBV(x-)) did not lead to productive HBV infection contrary to cells inoculated with wild type HBV particles (HBV(wt)). Although equal amounts of nuclear covalently closed circular HBV-DNA (cccDNA) demonstrated comparable uptake and nuclear import, active transcription was only observed from HBV(wt) genomes. Trans-complementation of HBx was able to rescue transcription from the HBV(x-) genome and led to antigen and virion secretion, even weeks after infection. Constant expression of HBx was necessary to maintain HBV antigen expression and replication. Finally, we demonstrated that HBx is not packaged into virions during assembly but is expressed after infection within the new host cell to allow epigenetic control of HBV transcription from cccDNA.Conclusions: Our results demonstrate that HBx is required to initiate and maintain HBV replication and highlight HBx as the key regulator during the natural infection process. (C) 2011 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.