Effect of basal core promoter and pre-core mutations on hepatitis B virus replication
Effect of basal core promoter and pre-core mutations on hepatitis B virus replication
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DOI：
10.1099/vir.0.83468-0
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发表时间：
2008-04-01
影响因子：
3.8
通讯作者：
Karayiannis, Peter
中科院分区：
文献类型：
--
作者：
Jammeh, Saffie;Tavner, Fiona;Karayiannis, Peter
有两种假说解释了B型肝炎病毒（HBV）感染后的暴发性结果，这两种假说可以同时适用：（i）基础核心启动子（BCP）突变增加病毒复制，允许病毒通过肝脏快速传播，和（ii）前核心（pre-C）突变消除了B e抗原（HBeAg）合成，消除了其耐受性;效果，导致强烈的免疫反应。本研究调查了这些突变对病毒复制效率和HBeAg产生的影响。使用共同的遗传背景，单独或组合检查BCP区中的A1762 T/G1764 A和T1753 C、C1766 T和T1768 A以及前C区中的G1896 A和G1899 A置换。用这些构建体转染Huh 7细胞，并使用实时PCR来定量释放的病毒体相关和细胞内HBV DNA、前基因组RNA和前C mRNA。此外，检测培养上清液中的乙型肝炎B表面抗原（HBsAg）和HBeAg。双BCP突变（A1762 T/G1764 A）和前C突变（G1896 A，G1899 A），无论是单独还是组合，对病毒的复制能力没有明显的影响。相反，在1766/1768、1762/1764/1766和1753/1762/1764位具有突变的克隆表现出增加的复制表型。正如预期的那样，在所有转染了G1896 A终止密码子突变的构建体的培养物中均未检测到HBeAg。相比之下，BCP区有额外突变的构建体比野生型有明显更低的HBeAg表达水平。因此，除了1762/1764处的核心启动子突变外，核心启动子突变似乎上调了病毒DNA复制，同时大大减少了HBeAg的产生。
There are two hypotheses explaining a fulminant outcome after hepatitis B virus (HBV) infection, both of which may be applicable at the same time: (i) basal core promoter (BCP) mutations increase viral replication, allowing rapid spread of the virus through the liver, and (ii) pre-core (pre-C) mutations abrogating hepatitis B e antigen (HBeAg) synthesis remove its tolerogenic; effect, leading to a vigorous immune response. This study investigated the effect of these mutations on virus replication efficiency and HBeAg production. Substitutions A1762T/G1764A and T1753C, C1766T and T1768A in the BCP region, and G1896A and G1899A in the pre-C region, were examined either alone or in combination, using a common genetic background. Huh7 cells were transfected with these constructs and real-time PCIR was used to quantify released virion-associated and intracellular HBV DNA, pregenomic RNA and pre-C mRNA. In addition, culture supernatants were tested for hepatitis B surface antigen (HBsAg) and HBeAg. The double BCP mutation (A1762T/G1764A) and the pre-C mutations (G1896A, G1899A), either alone or in combination, had no appreciable effect on the replication capacity of the virus. In contrast, clones with mutations at positions 1766/1768, 1762/1764/1766 and 1753/1762/1764 exhibited increased-replication phenotypes. HBeAg was undetectable in all cultures transfected with constructs bearing the G1896A stop-codon mutation, as expected. In contrast, constructs with additional mutations in the BCP region had appreciably lower levels of HBeAg expression than the wild type. Thus, core promoter mutations other than those at 1762/1764 appear to upregulate viral DNA replication and, at the same time, greatly reduce HBeAg production.