Origin of hepatitis delta virus mRNA
Origin of hepatitis delta virus mRNA
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DOI：
10.1128/jvi.74.16.7204-7210.2000
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发表时间：
2000-08-01
影响因子：
5.4
通讯作者：
Taylor, J
中科院分区：
文献类型：
--
作者：
Gudima, S;Wu, SY;Taylor, J
丁型肝炎病毒（HDV）相对于所有已知的动物病毒是独特的，特别是就其重定向宿主RNA聚合酶以转录其1,679个核苷酸（nt）环状RNA基因组的能力而言。在复制过程中，不仅积累了更多的基因组分子，而且还积累了它的确切补体——反基因组。此外，有相对少量的800-nt的抗基因组极性RNA被聚腺苷化，被认为是翻译单一和必需的HDV蛋白，即丁型抗原的mRNA。该mRNA的表征可以为HDV RNA定向RNA转录和加工的体内机制提供深入的见解。先前，我们发现该RNA的5′端位于大多数物种的nt 1630，目前的研究表明：(1)从感染hdv的土拨鼠的肝脏中提取的该RNA中至少有一些表现为包含5′帽结构；（ii）在受感染的肝脏中存在额外的多聚腺酰化的抗HDV RNA物种，其5‘端位于nt 1630位点以外至少202 nt甚至335 nt； （iii）在没有基因组复制的情况下，在dna定向HDV RNA转录后，在转染的细胞中未检测到nt 1630的5’端；（iv）尽管如此，使用纯化的人RNA聚合酶ii全酶和基因组RNA模板进行体外转录，我们没有检测到模板依赖性RNA合成的起始；我们观察到只有低水平的3‘端添加到模板中，这些新发现支持这样的解释，即HDV复制期间在nt 1630检测到的5’端代表了RNA定向RNA合成起始的特定位点，然后通过盖帽修饰。
Hepatitis delta virus (HDV) is unique relative to all known animal viruses, especially in terms of its ability to redirect host RNA polymerase(s) to transcribe its 1,679-nucleotide (nt) circular RNA genome. During replication there accumulates not only more molecules of the genome but also its exact complement, the antigenome. In addition, there are relatively smaller amounts of an 800-nt RNA of antigenomic polarity that is polyadenylated and considered to act as mRNA for translation of the single and essential HDV protein, the delta antigen. Characterization of this mRNA could provide insights into the in vivo mechanism of HDV RNA-directed RNA transcription and processing. Previously, we showed that the 5' end of this RNA was located in the majority of species, at nt 1630, The present studies show that (1) at least some of this RNA, as extracted from the liver of an HDV-infected woodchuck, behaved as if it contained a 5'-cap structure; (ii) in the infected liver there were additional polyadenylated antigenomic HDV RNA species with 5' ends located at least 202 nt and even 335 nt beyond the nt 1630 site, (iii) the 5' end at nt 1630 was not detected in transfected cells, following DNA-directed HDV RNA transcription, in the absence of genome replication, and (iv) nevertheless, using in vitro transcription with purified human RNA polymerase II holoenzyme and genomic RNA template, we did not detect initiation of template-dependent RNA synthesis; we observed only low levels of 3'-end addition to the template, These new findings support the interpretation that the 5' end detected at nt 1630 during HDV replication represents a specific site for the initiation of an RNA-directed RNA synthesis, which is then modified by capping.