不同毒株猪细小病毒VP2基因的克隆与序列分析

应用PCR扩增了猪细小病毒NJ-1株、NJ-2株、7909株和Vaccine株的VP2基因,分别克隆于pGEM-TEasy载体中,测定其核苷酸序列,并推导出相应的氨基酸序列,对其核苷酸和氨基酸序列进行分析和同源性比较。所测4个序列中,NJ-1株、NJ-2株和7909株序列均为1437bp,共编码479个氨基酸;而Vaccine序列为657bp,比其他毒株缺失780bp,共编码219个氨基酸。将所得4个序列与GenBank中NADL-2株、Kresse株、China株及VR-1株相应的核苷酸及氨基酸进行同源性比较,发现其核苷酸和氨基酸的同源性分别在97.7%~99.9%和97.2%~99.2%之间,具有高度同源性;通过绘制系统进化树可知,分离自国内的China株、NJ-1株、NJ-2株、7909株及Vaccine株亲缘性最为相近,与其他毒株的亲缘关系较远。

Molecular cloning and sequence analysis of VP2 genes from the different strains of porcine parvovirus

VP2 genes of NJ-1, NJ-2, 7 909 and Vaccine strains of porcine parvovirus(PPV)were amplified by PCR, and cloned into pGEM-T Easy vector, respectively. The sequencing analysis showed that VP2 genes from NJ-1, NJ-2 and 7 909 strains were all 1 437 bp in length, which encoded 479 amino acids, but that from the Vaccine strain was 657 bp, encoding 219 amino acids. Compared with other strains, 780 bp nucleotides were lost. Comparing the four sequences with those from NADL-2, Kresse, China and VR-1 strains in GenBank, we found that their homologies were 97.7%~99.9% in nucleotide sequences and 97.7%~99.2% in amino acid sequences, respectively. By the analysis of phylogenetic tree, it was found that china strain, NJ-1, NJ-2, 7 909 and Vaccine strains isolated from China had higher homologies with one another,but had lower homology with others from abroad.