2株猪圆环病毒2型ORF2的克隆及序列分析

Cloning and Sequence Analysis of ORF2 Gene of Two PCV-2 Strains

根据GenBank中猪圆环病毒2型(PCV-2)的核酸序列,设计一对引物,采用PCR方法从疑似断奶仔猪多系统衰竭综合征(PMWS)的死亡仔猪组织病料中扩增出ORF2基因,将其克隆到pMD18-T载体上,筛选获得重组质粒pMD18T-ORF2。序列分析表明,克隆的ORF2基因与其他PCV-2ORF2的分离株的同源性在91.5%～99.4%,与杭州分离株的同源性达到99.4%,表明我国各地区之间PCV-2的分离株存在较大的差异。

Using a pair of specific primers designed according to published ORF2 gene sequence of PCV-2, the ORF2 gene was amplified from the suspected PMWS samples by PCR. The amplified fragments were cloned into the pMD18-T vectors and the positive recombinant plasmids were designated PMD18-T-ORF2. The results indicated that it share 91.5 % to 99.4 % homology at their nucleotide level. There has only 91.5% nucleotide identity with Henna isolates and shared most high sequence identity of 99.4% with Zhejiang isolate,99.4%. The data indicated that there have genetic differences from different geographical regions.