Beimforde Nadine, Hanke Kirsten, Ammar Ismahen, Kurth Reinhard, Bannert Norbert
Robert Koch-Institut, ZBS 4, Nordufer 20, 13353 Berlin, Germany.
Virology. 2008 Feb 5;371(1):216-25. doi: 10.1016/j.virol.2007.09.036.
The human endogenous retrovirus-K113 (HERV-K113) is the most complete HERV known to date. It contains open reading frames for all viral proteins. Depending on ethnicity, up to 30% of the human population carries the provirus on chromosome 19. To facilitate molecular and functional studies, we have cloned the HERV-K113 sequence into a small plasmid vector and characterized its functional properties. Here we show that based on a substantial LTR-promoter activity, full length messenger RNA and spliced env-, rec- and 1.5 kb (hel)-transcripts are produced. The envelope protein of HERV-K113 is synthesized as an 85 kDa precursor that is found partially processed. The accessory Rec protein is highly expressed and accumulates in the nucleus. Expression analysis revealed synthesis of the Gag precursor and the protease. However, the cloned HERV-K113 provirus is not replication competent. It carries inactivating mutations in the reverse transcriptase gene. These mutations can be reversed to reconstitute the active enzyme, but the reversion is not sufficient to reconstitute replication capacity of the virus.
人类内源性逆转录病毒-K113（HERV-K113）是迄今为止已知的最完整的人类内源性逆转录病毒。它包含所有病毒蛋白的开放阅读框。根据种族不同，高达30%的人类群体在19号染色体上携带该前病毒。为便于进行分子和功能研究，我们已将HERV-K113序列克隆到一个小质粒载体中，并对其功能特性进行了表征。在此我们表明，基于大量的长末端重复序列（LTR）启动子活性，可产生全长信使核糖核酸（mRNA）以及剪接后的env-、rec-和1.5 kb（hel）转录本。HERV-K113的包膜蛋白作为一种85 kDa的前体合成，发现其部分已被加工。辅助性Rec蛋白高度表达并在细胞核中积累。表达分析显示了 gag 前体和蛋白酶的合成。然而，克隆的HERV-K113前病毒没有复制能力。它在逆转录酶基因中携带失活突变。这些突变可以被逆转以重建活性酶，但这种逆转不足以重建病毒的复制能力。
