人A组轮状病毒北京地方株VP4血清型特异片段编码基因的序列分析

轮状病毒是引起婴幼儿严重腹泻的重要病原，其第四基因编码主要中和抗原VP4，而VP4可裂解为VP8和VP5两个片段。VP8为抗原型特异性片段。克隆并测定了具有代表性的三个轮状病毒北京株VP4编码基因5′端（VPS＋VPS一部分）887个核苷酸序列并据此推导出其氨基酸序列。结果表明，相同血清型的地方株和标准株之间具有高度同源性（92％～966％），不同血清型间则变异较大（70．5％～71％）。氨基酸最大变异处位于aa84～172，并对胰酶作用位点在致病性中的可能性进行了讨论。

SEQUENCE ANALYSIS OF THE SEROTYPE SPERIFIC GENE FRAGMENT OF VP4 FROM THREE ROTAVIRUS FIELD STRAINS

Rotaviruses are the major pathogens that cause life threatening diarrhea in young children and animals. The 4th gene, encodes the nonglycosylated major neutralizing protein VP4 which can be cleaved into VP8 and VP5. The regions of the fourth genes coding for the VP8 protein, downstream cleavage site and the NH2 terminus of VP5 from three Beijing human rotavirus field strains (T65 P1A], R50P1B], N16P2]) were cloned and sequenced. Comparative analysis of the deduced amino acid sequences of these 887 bp fragments from three strains indicates a high degree of homology (92%-96.6%) between field and reference strains within the same serotype and a high degree of divergence (70.5%-71%) among different serotypes. Notably, the most divergence of amino acid sequence is located in a region delimited by aa 84-172 of VP8 protein. In addition, the possibility of trypsin cleavage sites in virulence is discussed.