Shiu S Y, Ayres M D, Gould E A
NERC Institute of Virology & Environmental Microbiology, Oxford, United Kingdom.
Virology. 1991 Jan;180(1):411-5. doi: 10.1016/0042-6822(91)90048-g.
The genomic RNA of louping ill virus coding for capsid, premembrane, membrane, and envelope proteins was cloned and sequenced. Hydrophilicity profiles of the deduced amino acid sequence shared homologous functional domains with other flaviviruses. The premembrane and envelope proteins contain N-glycosylation sites and conserved cysteine residues which are important for maintaining the secondary structures of the proteins. Sequence comparisons of louping ill envelope protein showed greater homology with tick-borne than mosquito-borne flaviviruses and greater homology with the western than the far eastern subtype of tick-borne encephalitis virus. With the capsid and membrane proteins, the degree of homology between louping ill and the western subtype was greater than that between the two subtypes, indicating very close evolutionary relationships between louping ill and the western subtype of tick-borne encephalitis. Thus, louping ill and tick-borne encephalitis may be varieties of a common tick-borne ancestral virus. The average amino acid sequence diversity between members of the tick-borne serogroup was significantly lower than that of mosquito-borne serogroups, suggesting that tick-borne flaviviruses have been subjected to different evolutionary immune selection pressure from the mosquito-borne viruses. Using the published model of tick-borne encephalitis envelope protein and our sequence data on louping ill virus, we have identified three discontinuous peptides (amino acids 81-88, 207-212, and 230-234) which may represent critical molecular determinants within the receptor binding site of tick-borne flaviviruses and may provide a specific genetic marker for these viruses.
对编码衣壳、前膜、膜和包膜蛋白的跳跃病病毒基因组RNA进行了克隆和测序。推导的氨基酸序列的亲水性图谱与其他黄病毒共享同源功能域。前膜和包膜蛋白含有N-糖基化位点和保守的半胱氨酸残基，这些对于维持蛋白质的二级结构很重要。跳跃病包膜蛋白的序列比较显示，与蜱传黄病毒的同源性高于蚊传黄病毒，与蜱传脑炎病毒西方亚型的同源性高于远东亚型。在衣壳和膜蛋白方面，跳跃病与西方亚型之间的同源程度大于两个亚型之间的同源程度，表明跳跃病与蜱传脑炎西方亚型之间存在非常密切的进化关系。因此，跳跃病和蜱传脑炎可能是一种常见蜱传祖病毒的变种。蜱传血清群成员之间的平均氨基酸序列多样性明显低于蚊传血清群，这表明蜱传黄病毒受到了与蚊传病毒不同的进化免疫选择压力。利用已发表的蜱传脑炎包膜蛋白模型和我们关于跳跃病病毒的序列数据，我们确定了三个不连续的肽段（氨基酸81-88、207-212和230-234），它们可能代表蜱传黄病毒受体结合位点内的关键分子决定因素，并可能为这些病毒提供一个特定的遗传标记。
