犬冠状病毒小膜蛋白基因的分子克隆与序列分析

首次对犬冠状病毒(CCV)V1株和DXMV株小膜蛋白(SM)基因进行了克隆和序列测定.用RT-PCR对分离的CCV V1和DXMV野毒株SM基因进行了扩增,并将其克隆到pMD18-T中进行核苷酸序列测定.结果两毒株SM基因ORF全长均为246bp,编码82个氨基酸;与GenBank中CCV标准毒株Insavc-1 SM基因相比,核苷酸和推导的氨基酸序列同源性分别为100%、92.1%和100%、90.9%.DXMV株与Insavc-1株SM基因相比有9个碱基发生了改变,导致4个氨基酸发生变化.对冠状病毒科中不同的冠状病毒SM基因及其推导的氨基酸序列聚类分析表明,冠状病毒可分为4个群,群内不同冠状病毒SM基因及其蛋白显示出很高的同源性,而不同群之间的同源性却较低.

Molecular cloning and sequence analysis of small membrane protein gene of canine coronavirus

Small membrane protein genes(SM) of canine coronavirus yield strain V1 and DXMV were firstly cloned and sequenced.Small membrane protein gene of canine coronavirus strain V1 and DXMV were amplified by RT-PCR with a pair of specific primers.Then positive PCR product was purified and cloned into pMD18-T.The correct recombinant was used for sequencing.The complete lengths of SM gene of CCV strain V1 and DXMV were all 246 bp,which encoded 82 amino acids.Compared with SM gene of strain Insavc-1,the homologies of nucleotide and amino acid were 100?%,92.1?% and 100?%,90.9?% respectively.There were 9 differences in nucleotide,which resulted in 4 different amino acids for strain DXMV,compared with SM gene of Insavc-1.Phylogenetic trees based on homologies of SM gene and deduced amino acid of different coronavirus showed that coronavirus can be divided into 4 groups.The coronavirus in one group exhibit high identity,while low identity exist in different groups.