Mechanism of suppression of hepatitis B virus precore RNA transcription by a frequent double mutation
Mechanism of suppression of hepatitis B virus precore RNA transcription by a frequent double mutation
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DOI：
10.1128/jvi.73.2.1239-1244.1999
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发表时间：
1999-02-01
影响因子：
5.4
通讯作者：
Ou, JH
中科院分区：
文献类型：
--
作者：
Li, J;Buckwold, VE;Ou, JH
在从具有慢性肝炎症状的 HBV 患者中分离的乙型肝炎病毒 (HBV) 基因组中经常发现将核苷酸 1765 从 A 转换为 T 和核苷酸 1767 从 G 转换为 A 的双突变。这种双突变位于控制前核心RNA和核心RNA转录的核心启动子中。此外，这种双突变也存在于X蛋白编码序列中，将密码子130从Lys转换为Met，将密码子131从Val转换为Ile。先前的研究表明，这种双突变去除了核心启动子中的核受体结合位点，特异性抑制前核心RNA转录，并增强病毒复制。在这项研究中，我们进一步研究了这种双突变如何抑制前核 RNA 转录。我们发现这种双突变不仅去除了核受体结合位点，还创建了 HNF1 转录因子结合位点。使用Huh7肝癌细胞的进一步转染研究表明，核受体结合位点的去除对HBV RNA的转录没有影响，X蛋白序列中的双密码子变化抑制了前核心和核心RNA的转录，而HNF1结合位点的创建恢复了核心RNA的水平。因此，这种频繁的双核苷酸突变对前核RNA转录的特异性抑制是多种因素综合作用的结果。
A double mutation which converts nucleotide 1765 from A to T and nucleotide 1767 from G to A is frequently found in the hepatitis B virus (HBV) genome isolated from HBV patients with chronic hepatitis symptoms. This double mutation is located in the core promoter that controls the transcription of the precore RNA and the core RNA. In addition, this double mutation also resides in the X protein coding sequence, converting codon 130 from Lys to Met and codon 131 from Val to Ile. Previous studies indicate that this double mutation removes a nuclear receptor binding site in the core promoter, suppresses specifically precore RNA transcription, and enhances viral replication. In this study, we further investigated how this double mutation suppresses precore RNA transcription. We found that this double mutation not only removed the nuclear receptor binding site but also created an HNF1 transcription factor binding site. Further transfection studies using Huh7 hepatoma cells indicate that the removal of the nuclear receptor binding site has no effect on the transcription of HBV RNAs, the two-codon change in the X protein sequence suppresses the transcription of both precore and core RNAs, and the creation of the HNF1 binding site restores the core RNA level. Hence, the specific suppression of precore RNA transcription by this frequent double-nucleotide mutation is the combined result of multiple factors.