RELATION OF OUTER CAPSID PROTEIN VP4 OF HUMAN AND ANIMAL ROTAVIRUSES

通过引物延伸，我们确定了该基因的完整核苷酸序列。 人轮状病毒K8株外衣壳蛋白VP4基因。 VP4基因全长2,359个碱基对，5‘和3’非编码 分别为9个和25个核苷酸的区域。该基因含有一个很长的 2,325个碱基的开放阅读框架，能够编码775个蛋白质 氨基酸。与其他人类轮状病毒相比，轮状病毒的VP4 菌株K8在第135位残基后插入1个氨基酸为 在猴轮状病毒株中发现，此外，它还有一个缺失 1个氨基酸(575个残基)。K8的VP4基因只有60%-70% 与其他强毒株VP4的氨基酸序列同源性 轮状病毒。这是一个不寻常的观察，因为所有其他VP4 人轮状病毒强毒株显示90%以上的氨基酸 同源。相反，K8株的VP7氨基酸序列为 与其他1型人类轮状病毒非常相似(大于 98%的同源性)。 在我们之前的研究中，交叉反应中和表位 对人轮状病毒的VP4进行了分析，发现K8携带独特的VP4 中和表位。该毒株属于亚群II和 血清1型，不被六种抗VP4中和中的任何一种中和 与血清1、3和4或血清1反应的单抗 通过4株人轮状病毒。因此，K8毒株似乎有一种 独有的VP4基因以前没有被描述过。

By primer extension, we determined the complete nucleotide sequence of the gene encoding the outer capsid protein VP4 of human rotavirus strain K8. The VP4 gene is 2,359 base pairs in length with 5'- and 3'-noncoding regions of 9 and 25 nucleotides, respectively. The gene contains a long open reading frame of 2,325 bases capable of coding for a protein of 775 amino acids. When compared to other human rotaviruses, the VP4 of the strain K8 had an insertion of one amino acid after the l35th residue as found in simian rotavirus strains, and, in addition, it had a deletion of one amino acid (575th residue). The VP4 gene of K8 was only 60-70% homologous in amino acid sequence to the VP4 of other virulent human rotaviruses. This is an unusual observation since the VP4s of all other virulent human rotavirus strains exhibit greater than 90% amino acid homology. In contrast, the VP7 amino acid sequence of the K8 strain was quite similar to that of other serotype 1 human rotaviruses (greater than 98% homology). In our previous study in which the cross-reactive neutralization epitopes on VP4 of human rotaviruses were analyzed, K8 was found to bear unique VP4 neutralization epitopes. This strain, which belongs to subgroup II and serotype 1, was not neutralized by any of six anti-VP4 neutralizing monoclonal antibodies which reacted with serotype 1, 3 and 4, or serotype 1 through 4 human rotavirus strains. Thus, the K8 strain appears to have a unique VP4 gene previously not described.