SEQUENCE OF THE FOURTH ROTAVIRUS GENE AND ITS ROLE IN VIRULENCE

8个人第四基因的全核苷酸序列 轮状病毒的双脱氧链末端测定 方法。编码VP3的基因4全长2359个碱基对 并包含一个2325个碱基的长开放阅读框， 能够编码775个氨基酸的蛋白质，有5‘和3’ 非编码区分别为9个和25个核苷酸。VP3 的人类轮状病毒含有相同的N末端氨基酸 序列，在两个胰酶上有精氨酸的保守性 裂解位点和氨基酸簇的保守性 在两个VP3裂解产物的不同区域，VP8和 VP5。在VP3蛋白序列中有14个区域 表现出最大的变异性。这些区域可能代表 潜在的抗原性部位。猪瘟病毒氨基酸序列的比对分析 无症状和强毒的人类轮状病毒株表明 无症状患者的高度同源性(96%或以上) 病毒(血清型1、2、3和4型)，而 无症状菌株和强毒病毒的数量要少得多。 (76%)。氨基酸序列高度保守(90- 93%)也在3株强毒株(血清型1， 3和4)。VP3蛋白序列的第89位是一种氨基酸 在无症状的轮状病毒中，酸是保守的，而 不同的氨基酸在强毒轮状病毒之间是保守的。 值得注意的是，其中三个差异位于短短6个月内 VP8和VP5之间的氨基酸裂解区。这是有可能的 这种序列的部分或全部二态现象可能是 对于这两组人类毒力的差异 轮状病毒。

The complete nucleotide sequence of the fourth gene of 8 human rotaviruses was determined by the dideoxy chain-termination method. Gene 4, which encodes VP3, is 2359 base pairs in length and contains a single long open reading frame of 2325 bases, capable of coding for a protein of 775 amino acids, with 5' and 3' noncoding regions of 9 and 25 nucleotides respectively. The VP3 of human rotaviruses contains identical N-terminal amino acid sequences, and there is conservation of arginine at the two trypsin cleavage sites as well as conservation of clusters of amino acids in different regions of the two VP3 cleavage products, VP8 and VP5. There are 14 regions in the VP3 protein sequence which exhibit the greatest variability. These regions may represent potential antigenic sites. Alignment of amino acid sequences of asymptomatic and virulent human rotavirus strains indicates a high degree of homology (96% or more) among the asymptomatic viruses (serotypes 1, 2, 3 and 4), while homology between asymptomatic strains and virulent viruses is considerably less (76%). A high degree of conservation of amino acid sequence (90- 93%) is also observed among 3 of the virulent strains (serotypes 1, 3 and 4). At 89 positions in the protein sequence of VP3, an amino acid is conserved among asymptomatic rotaviruses, while a different amino acid is conserved among virulent rotaviruses. Notably, three of these differences are located within the short 6 amino acid cleavage region between VP8 and VP5. It is possible that some or all of this sequence dimorphism may be responsible for the difference in virulence of these two groups of human rotaviruses.