鸡贫血病毒vp3基因克隆、序列分析和比较

克隆了从我国哈尔滨分离的一株鸡贫血病毒（CAV）的vp3基因，并对之进行了测序。该基因的开放读码枢由366bp组成，编码121个氨基酸，氨基酸组成具有已报道VP3的典型特点。本次克隆的基因与GenBank收录的CAV的vp3基因进行序列比较，同源性至少为98％。与国内报道的山东株SJ1的vp3基因有3个核苷酸的差异，表明国内的CAV毒株已经产生了一些分化。在EMBL中比较本次克隆的VP3蛋白一级结构，与之差异最大的是马来西亚分离株的VP3，有5个氨基酸残基不同，同源性为96％。同时收集EMBL中的CAV的VP3蛋白绘制进化树，我国哈尔滨分离的CAV毒株与CIA进化关系最近，而与Cux-1的2个衍生株QDWX1、QDWX3进化关系最远。这些结果进一步证明了CAV在遗传方面是较保守的病毒，来自哈尔滨的CAV不是CAV的一个独立分支。

Cloning,Sequencing and Comparing of vp3 Gene of Chicken Anemia Virus

The vp3 gene of chicken anemia virus was amplified by polymerase chain reaction from liver of chicken infected by chicken anemia virus in Harbin of China and cloned into pUC18.The recombinant plasmid was identified by restriction digestion.The sequence of the gene was analyzed with F promer by TaKaRa Biotechniques(Dalian,China).Comparing the gene with all genes in GenBank and Shandong strain SJ1 of China,It was found that it had well homology to the reported vp3 genes in GenBank.Amino sequence of the VP3 protein was analyzed with alignment in EMBL and the genetree is drawn with BLAST2 & Orthologue.It was found that the VP3 protein and VP3 of other CAVs were identical from 96% to 100% of amino acid positions.Results confirmed the limited genetic variability of CAV and the CAV isolated in Harbin is not found on a new separate branch.