2种家养动物朊蛋白基因的扩增与分析

Prion Protein Gene Amplification and Sequences Analysis of Two Local Domestic Animals

采用PCR方法扩增了云南矮马和北京油鸡的PrP^C基因，并进行序列测定，结合已发表种属朊病毒基因序列，运用分子生物学软件进行同源性分析。结果表明，云南矮马PrP^C基因与已报道的马PrP^C基因比较，其同源性达99％，氨基酸同源性达100％。与牛PrP^C基因比较，同源性达89％，氨基酸同源性达91％。北京油鸡PrP^C基因与鸡的已知序列比较，同源性达99％；与鸭、鸽、鹌鹑的已知序列比较，同源性94％～97％。其翻译的氨基酸序列与鸡的已知序列比较，同源性达99％，与鸭、鸽、鹌鹑比较，氨基酸同源性88％～99％。从本试验结果来看，云南矮马PrP^C基因与牛的PrP^C基因同源性较远，因此感染牛源朊病毒的风险较小，禽类与哺乳动物PrP^C氨基酸属于2个不同的进化分支，因此哺乳动物海绵状脑病不易传染给禽类或引起朊蛋白构型上的改变。这些结果可为海绵状脑病种间屏障补充详细的数据，也为制定相关预防控制措施提供了一些理论依据。

The PrP^C genes of Yunnan pony and Beijing yellow chicken were amplified by PCR ,and the sequences were compared with those published of some species using molecular biological softwares. The results showed that PrP^C gene homology of Yunnan pony reached 99% and amino acid homology arrived at 100% as compared to horse PrP^C ;89% and 91 % respectively as compared to cattle PrP^C. Furthermore ,PrP^C gene homology of Beijing yellow chicken reached 99 % ,and amino acid homology arrived at 99% as compared to White Leghorn,varied between 94% and 97% and between 88% and 99% respectively as compared to duck,pigeon and quail PrPs. These data revealed that the PrP^C of Yunnan pony was remote to bovine PrP^C ,therefore, the infection risk by cattle-derived prions might be small ,and the bird PrP^C belonged to a different phylogenetic branch as compared with mammal,which maybe suggest bird PrP^C can not infect the mammal or can not induce prion change. Thus ,these resuits constituted an important complementary part for the research of species barrier mechanism in the transmissible spongiform encephalopathy disease,and provided some theoretical basis for making protected and control measures.