狐源犬瘟热病毒核衣壳蛋白基因的克隆与序列分析

根据GenBank上发表的犬瘟热病毒(CDV)N基因核酸序列,设计一对CDVN基因特异性引物,采用RT-PCR扩增狐源CDV泰安分离株(CDV-FOX-TA)的N基因,将PCR产物克隆入pMD18-T载体,进行测序分析.结果表明,CDV-FOX-TA N基因含有1个ORF,全长1572 bp,共编码523个氨基酸.CDV-FOX-TAN基因与CDV疫苗株Onderstepoort、Convac的N基因的同源性分别为96.0%和95.9%,与CDV野毒株N基因的同源性在98.4%～98.9%之间.CDV-FOX-TA N蛋白含有Tyr-Pro-Ala-Leu-Gly-Leu-His-Glu-Phe九肽序列,是T细胞表位,可致敏靶细胞,在CDVN蛋白中高度保守.对CDV N基因进行系统发生分析,结果发现CDV-FOX-TA与CDV强毒株的亲缘关系较为密切.

Cloning and Sequence Analysis of the N Gene of Canine Distemper Virus Tai'an Isolate in a Fox

One pair of primers was designed according to the N genes of canine distemper virus strains reported in GenBank. The N protein gene of CDV-FOX-TA was amplified with the primers by RT-PCR. The PCR product was cloned into pMD18-T. And the positive recombinant was identified, sequenced and analyzed. As a result, the large open reading frame of the N gene of CDV-FOX-TA included 1572 bp, which encoded 523 amino acids. The nucleotide homology of the N genes between CDV-FOX-TA and CDV Ondertepoort strain was 96.0%, and it was 95.9% between CDV-FOX-TA and CDV Convac strain. However, the nucleotide homologies of the N genes of CDV-FOX-TA and the CDV wild strains, was from 98.4% to 98.9%. A nine-peptide sequence in the N protein of CDV-FOX-TA was Tyr-Pro-Ala- Leu-Gly-Leu-His-Glu-Phe, which was T lymphocyte defined antigen and senstized target cells. On the basis of phylogenetic analysis, it implied that CDV-FOX-TA and the CDV wild strains had the same ancestor.