Common evolutionary origin of hepatitis B virus and retroviruses.
Common evolutionary origin of hepatitis B virus and retroviruses.
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DOI：
10.1073/pnas.83.8.2531
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发表时间：
1986-04
影响因子：
11.1
通讯作者：
R. Miller;W. Robinson
中科院分区：
文献类型：
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作者：
R. Miller;W. Robinson
B型肝炎病毒（HBV）虽然被归类为双链DNA病毒，但最近已显示通过RNA中间体的逆转录来复制。此外，已发现推定的病毒聚合酶与逆转录病毒的逆转录酶共享氨基酸同源性。使用计算机辅助的DNA和蛋白质序列分析，我们检查了13个嗜肝DNA病毒分离株（9人，2鸭，土拨鼠，和一个地松鼠）的基因组，发现嗜肝DNA病毒基因组的其他保守区域共享同源性的C型逆转录病毒和逆转录病毒样内源性人类DNA元件的基因组的相应区域。具体而言，HBV基因组中最高度保守的序列，位于或接近第一链HBV DNA合成的起始位点，在67个核苷酸上与U 5区同源，U 5区是逆转录病毒长末端重复序列中的可比区域。在一个高度保守的（即，16个核苷酸序列和7个核苷酸序列的同源性为97%。此外，我们发现，高度保守的HBV核心，或核衣壳，蛋白共享41%的同源性超过98个氨基酸的羧基末端区域的p30 gag核衣壳蛋白的C型逆转录病毒。在这两种情况下，与先前报道的聚合酶同源性一样，HBV与鼠白血病/肉瘤逆转录病毒最同源。进一步的分析揭示了嗜肝DNA病毒和逆转录病毒基因组之间的其他相似性。总之，我们的研究结果表明，HBV和逆转录病毒有一个共同的进化起源，与HBV通过删除过程中产生的逆转录病毒，或逆转录病毒样，祖。
Hepatitis B virus (HBV), although classified as a double-stranded DNA virus, has been shown recently to replicate by reverse transcription of an RNA intermediate. Also, the putative viral polymerase has been found to share amino acid homology with reverse transcriptase of retroviruses. Using computer-assisted DNA and protein sequence analyses, we examined the genomes of 13 hepadnavirus isolates (nine human, two duck, one woodchuck, and one ground squirrel) and found that other conserved regions of the hepadnavirus genome share homology to corresponding regions of the genomes of type C retroviruses and retrovirus-like endogenous human DNA elements. Specifically, the most highly conserved sequence of the HBV genome, positioned at or near the initiation site for first-strand HBV DNA synthesis, is homologous over 67 nucleotides to the U5 region, a comparable region in retrovirus long terminal repeats. Within a highly conserved (i.e., 90%) 16-nucleotide sequence a heptanucleotide sequence CCTTGGG is 97% homologous between 27 virus isolates. Also, we found that the highly conserved HBV core, or nucleocapsid, protein shares 41% homology over 98 amino acids with the carboxyl-terminal region of the p30 gag nucleocapsid protein of type C retroviruses. In both cases, as with the previously reported polymerase homology, HBV is most homologous to the murine leukemia/sarcoma retroviruses. Further analysis revealed additional similarities between hepadnavirus and retroviral genomes. Taken together, our results suggest that HBV and retroviruses have a common evolutionary origin, with HBV arising through a process of deletion from a retrovirus, or retrovirus-like, progenitor.