Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University Guangzhou, China ; Institute of Virology, University Hospital of Essen, University of Duisburg Essen Essen, Germany.
Front Genet. 2013 Oct 14;4:202. doi: 10.3389/fgene.2013.00202.
The hepatitis B virus (HBV) genome forms a covalently closed circular DNA (cccDNA) minichromosome that persists in the nucleus of virus-infected hepatocytes. HBV cccDNA serves as the template for viral mRNA synthesis and is subject to epigenetic regulation by several mechanisms, including DNA methylation and histone acetylation. Recently, microRNAs (miRNAs), a class of small non-coding RNAs, were also directly connected to the epigenetic machinery through a regulatory loop. Epigenetic modifications have been shown to affect miRNA expression, and a sub-group of miRNAs (defined as epi-miRNAs) can directly target effectors of the epigenetic machinery. In this review, we will summarize recent findings on the epigenetic mechanisms controlling HBV cccDNA function, primarily focusing on the epi-miRNA functions operating in HBV replication. Investigation of the epigenetic regulation of HBV replication may help to discover novel potential therapeutic targets for drug development with the goal to eradicate the HBV cccDNA pool in hepatocytes.
乙型肝炎病毒 (HBV) 基因组形成共价闭合环状 DNA (cccDNA) 微染色体,存在于病毒感染的肝细胞的细胞核中。HBV cccDNA 作为病毒 mRNA 合成的模板,并受到几种机制的表观遗传调控,包括 DNA 甲基化和组蛋白乙酰化。最近,miRNAs(miRNA),一类小的非编码 RNA,也通过一个调节环直接与表观遗传机制相连。表观遗传修饰已被证明会影响 miRNA 的表达,而一小部分 miRNA(定义为 epi-miRNA)可以直接靶向表观遗传机制的效应物。在这篇综述中,我们将总结最近关于控制 HBV cccDNA 功能的表观遗传机制的发现,主要集中在 epi-miRNA 在 HBV 复制中的功能。对 HBV 复制的表观遗传调控的研究可能有助于发现新的潜在治疗靶点,以开发药物,目标是清除肝细胞中的 HBV cccDNA 池。