Sargan D R, Bennet I D, Cousens C, Roy D J, Blacklaws B A, Dalziel R G, Watt N J, McConnell I
Department of Veterinary Pathology, University of Edinburgh, U.K.
J Gen Virol. 1991 Aug;72 ( Pt 8):1893-903. doi: 10.1099/0022-1317-72-8-1893.
We have isolated a maedi-visna-like virus from the peripheral blood mononuclear cells of a British sheep displaying symptoms of arthritis and pneumonia. After brief passage in fibroblasts this virus (designated EV1) was used to infect choroid plexus cells. cDNA clones of the virus were prepared from these cells and sequenced. Gaps between non-overlapping clones were filled using gene amplification by the polymerase chain reaction. The genome structure is similar to that described for visna virus strain 1514, and differs from that described for visna virus strain SA-OMVV in not having a W reading frame. Overall the genome differs by about 20% between each of these strains, but there is fivefold variation in the amount of divergence of derived amino acid sequences of different open reading frames. Two sequenced EV1 clones each contain only one copy of the 43 bp repeat, with paired AP-1 sites, which is a feature of other ruminant lentiviral long terminal repeats (LTRs). However, analysis of viral DNA in infected cells by gene amplification shows that LTRs with two repeats do occur, albeit at a relatively low frequency.
我们从一只出现关节炎和肺炎症状的英国绵羊的外周血单核细胞中分离出了一种梅迪-维斯纳样病毒。该病毒（命名为EV1）在成纤维细胞中短暂传代后，用于感染脉络丛细胞。从这些细胞中制备了该病毒的cDNA克隆并进行测序。使用聚合酶链反应进行基因扩增来填补非重叠克隆之间的缺口。其基因组结构与维斯纳病毒1514株的结构相似，与维斯纳病毒SA-OMVV株的结构不同之处在于没有W读码框。总体而言，这些毒株之间的基因组差异约为20%，但不同开放阅读框衍生氨基酸序列的差异量存在五倍的变化。两个测序的EV1克隆每个仅包含一个43 bp重复序列的拷贝，带有配对的AP-1位点，这是其他反刍动物慢病毒长末端重复序列（LTR）的一个特征。然而，通过基因扩增对感染细胞中的病毒DNA进行分析表明，确实存在具有两个重复序列的LTR，尽管频率相对较低。
