Williams C F, Inoue T, Lucus A M, Zanotto P M, Roy P
Department of Biochemistry, University of Oxford and NERC Institute of Virology and Environmental Microbiology, UK.
Virus Res. 1998 Jan;53(1):53-73. doi: 10.1016/s0168-1702(97)00131-7.
The amino acid sequences of four major capsid proteins of African horse sickness virus (serotype 6, AHSV-6) have been determined from analyses of cDNA clones representing the L2, L3, M6 and S7 RNA segments. The AHSV-6 L3 RNA segment has an open reading frame of 2715 base pairs and encodes the inner capsid protein VP3 which comprises 905 amino acids. The VP3 layer forms the subcore of the virion and is surrounded by the VP7 protein which is encoded by the S7 gene. The AHSV-6 S7 gene was found to be 1047 nucleotides in length with a coding capacity for the VP7 protein of 349 amino acids. These core proteins are encapsulated by the outer capsid proteins VP5 and VP2 which are encoded by the M6 and L2 genes respectively. The M6 gene of AHSV-6 was determined to be 1564 nucleotides in length and encoded a protein product of 504 amino acids while the L2 gene comprised 3203 nucleotides which encoded a predicted protein product of 1051 amino acids. Comparison of these four sequences with the core protein sequences of other serotypes of African horse sickness virus, Bluetongue virus which infects sheep, and Epizootic haemorrhagic disease virus of deer, demonstrated that despite the pathobiological properties and host range of these distinct orbiviruses, extreme conservation is evident within the capsid genes. Sequence analyses also suggested that the similarity levels between serogroups depict the structure and function of the individual capsid proteins. The data indicated that the evolution of the capsid genes of gnat transmitted orbiviruses is strongly influenced by functional and structural constraints.
通过对代表非洲马瘟病毒（血清型6，AHSV - 6）L2、L3、M6和S7 RNA片段的cDNA克隆进行分析，已确定了该病毒四种主要衣壳蛋白的氨基酸序列。AHSV - 6的L3 RNA片段有一个2715个碱基对的开放阅读框，编码由905个氨基酸组成的内衣壳蛋白VP3。VP3层形成病毒粒子的亚核心，并被由S7基因编码的VP7蛋白所包围。发现AHSV - 6的S7基因长度为1047个核苷酸，编码由349个氨基酸组成的VP7蛋白。这些核心蛋白被分别由M6和L2基因编码的外衣壳蛋白VP5和VP2所包裹。确定AHSV - 6的M6基因长度为1564个核苷酸，编码一个由504个氨基酸组成的蛋白产物，而L2基因包含3203个核苷酸，编码一个预测的由1051个氨基酸组成的蛋白产物。将这四个序列与非洲马瘟病毒其他血清型、感染绵羊的蓝舌病毒以及鹿的流行性出血病病毒的核心蛋白序列进行比较，结果表明，尽管这些不同环状病毒具有病理生物学特性和宿主范围，但衣壳基因内存在明显的高度保守性。序列分析还表明，血清群之间的相似性水平描绘了各个衣壳蛋白的结构和功能。数据表明，蚋传播的环状病毒衣壳基因的进化受到功能和结构限制的强烈影响。
