Cell Type Diversity in Hepatitis B Virus RNA Splicing and Its Regulation
Cell Type Diversity in Hepatitis B Virus RNA Splicing and Its Regulation
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DOI：
10.3389/fmicb.2019.00207
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发表时间：
2019-02-08
影响因子：
5.2
通讯作者：
Suzuki, Tetsuro
中科院分区：
文献类型：
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作者：
Ito, Noriomi;Nakashima, Kenji;Suzuki, Tetsuro
尽管B型肝炎病毒（HBV）的RNA剪接在B型肝炎患者的肝脏中以及在复制病毒基因组的培养细胞中是常见的，但其在HBV生命周期中的生物学意义和详细的调控机制仍在很大程度上不清楚。在这项研究中，我们发现HBV剪接的3.5 kb的前基因组RNA，这是有效地剪接在人肝癌细胞，但不是在来自人肝星状细胞，小鼠肝癌和人非肝细胞的细胞类型依赖性。RNA剪接可能是HBV宿主范围限制的决定因素之一。鉴于这一发现表明HBV和猿猴病毒40之间剪接效率的细胞类型依赖性的差异，我们进行了内含子交换实验。结果表明，存在假定的外显子剪接增强子，可能在细胞类型依赖的方式工作。连同进一步的突变分析，一个新的50-nt内含子剪接沉默子，其二级结构是非常保守的HBV毒株，被确定。看起来这种内含子沉默子有效地独立于细胞背景发挥作用。
Although RNA splicing of hepatitis B virus (HBV) is a commonly observed in livers of hepatitis B patients as well as in the cultured cells replicating the viral genome, its biological significance in the HBV life cycle and the detailed regulatory mechanisms are still largely unclear. In this study, we found cell-type dependency of HBV splicing of the 3.5 kb pregenomic RNA, which is efficiently spliced in human hepatoma cells but not in cells derived from human hepatic stellate, mouse hepatoma and human non-hepatic cells. It may be likely that RNA splicing is one of the determinants of host range restriction of HBV. Given the finding indicating the difference in cell-type dependency of the splicing efficiency between HBV and simian virus 40, we carried out intron-swapping experiments. The results suggest the presence of putative exonic splicing enhancer that possibly works in the cell-type dependent fashion. Together with further mutational analyses, a novel 50-nt intronic splicing silencer, whose secondary structure is well conserved among the HBV strains, was identified. It appears that this intronic silencer functions effectively independent of cell backgrounds.