Lavie Laurence, Medstrand Patrik, Schempp Werner, Meese Eckart, Mayer Jens
Department of Human Genetics, Building 60, University of Saarland, Medical Faculty, 66421 Homburg, Germany.
J Virol. 2004 Aug;78(16):8788-98. doi: 10.1128/JVI.78.16.8788-8798.2004.
The human genome harbors numerous distinct families of so-called human endogenous retroviruses (HERV) which are remnants of exogenous retroviruses that entered the germ line millions of years ago. We describe here the hitherto little-characterized betaretrovirus HERV-K(HML-5) family (named HERVK22 in Repbase) in greater detail. Out of 139 proviruses, only a few loci represent full-length proviruses, and many lack gag protease and/or env gene regions. We generated a consensus sequence from multiple alignment of 62 HML-5 loci that displays open reading frames for the four major retroviral proteins. Four HML-5 long terminal repeat (LTR) subfamilies were identified that are associated with monophyletic proviral bodies, implying different evolution of HML-5 LTRs and genes. Sequence analysis indicated that the proviruses formed approximately 55 million years ago. Accordingly, HML-5 proviral sequences were detected in Old World and New World primates but not in prosimians. No recent activity is associated with this HERV family. We also conclude that the HML-5 consensus sequence primer binding site is identical to methionine tRNA. Therefore, the family should be designated HERV-M. Our study provides important insights into the structure and evolution of the oldest betaretrovirus in the primate genome known to date.
人类基因组中存在众多不同的所谓人类内源性逆转录病毒（HERV）家族，它们是数百万年前进入种系的外源性逆转录病毒的残余物。我们在此更详细地描述了迄今特征较少的β逆转录病毒HERV-K（HML-5）家族（在Repbase中命名为HERVK22）。在139个前病毒中，只有少数位点代表全长前病毒，许多缺乏gag蛋白酶和/或env基因区域。我们通过对62个HML-5位点的多序列比对生成了一个共有序列，该序列显示了四种主要逆转录病毒蛋白的开放阅读框。鉴定出四个HML-5长末端重复序列（LTR）亚家族，它们与单系前病毒体相关，这意味着HML-5 LTR和基因的进化不同。序列分析表明，前病毒大约在5500万年前形成。因此，在旧世界和新世界灵长类动物中检测到了HML-5前病毒序列，但在原猴亚目中未检测到。这个HERV家族没有近期的活性。我们还得出结论，HML-5共有序列引物结合位点与甲硫氨酸tRNA相同。因此，该家族应命名为HERV-M。我们的研究为迄今为止已知的灵长类基因组中最古老的β逆转录病毒的结构和进化提供了重要见解。
