Functional characterization of hepatitis B virus core promoter mutants revealed transcriptional interference among co-terminal viral mRNAs
Functional characterization of hepatitis B virus core promoter mutants revealed transcriptional interference among co-terminal viral mRNAs
复制标题
乙型肝炎病毒核心启动子突变体的功能特征揭示了共末端病毒 mRNA 之间的转录干扰
DOI：
10.1099/jgv.0.000590
复制
发表时间：
2016-10-01
影响因子：
3.8
通讯作者：
Tong, Shuping
中科院分区：
文献类型：
--
作者：
Chen, Chaoyang;Jia, Haodi;Tong, Shuping
Hepatitis B virus (HBV) has a 3.2 kb circular DNA genome. It employs four promoters in conjunction with a single polyadenylation signal to generate 3.5, 2.4, 2.1 and 0.7 kb co-terminal RNAs. The 3.5 kb RNA is subdivided into the precore RNA for e-antigen expression and pregenomic RNA for genome replication. When introduced to a genotype A clone, several core promoter mutations markedly enhanced HBV genome replication, but suppressed e-antigen expression through up-regulation of pregenomic RNA at the expense of precore RNA. In this study, we found such mutations also diminished envelope proteins and hepatitis B surface antigen, products of the 2.1 and 2.4 kb subgenomic RNAs. Indeed, Northern blot analysis revealed overall increase in 3.5 kb RNA, but reduction in all subgenomic RNAs. To validate transcriptional interference, we subcloned 1.1x, 0.7x and 0.6x HBV genome, respectively, to a vector with or without a cytomegalovirus (CMV) promoter at the 5' end, so as to produce the pregenomic RNA, 2.4 kb RNA, and 2.1 kb RNA in large excess or not at all. Parallel transfection of the three pairs of constructs into a human hepatoma cell line confirmed the ability of pregenomic RNA to suppress all subgenomic transcripts and established the ability of the 2.4 and 2.1 kb RNAs to suppress the 0.7 kb RNA. Consistent with our findings, pregenomic RNA of the related duck HBV has been reported to interfere with transcription of the subgenomic RNAs. Transcriptional interference might explain why HBV produces so little 0.7 kb RNA and HBx protein despite a strong X promoter.
