蒙原羚朊蛋白基因的序列分析和多态性研究

Sequences Analysis and Polymorphism Research of the Prion Protein Gene in Mongolian Gazelles( Procapra gutturosa)

传染性海绵状脑病(TSE)是发生于人和动物神经系统的退行性疾病,影响着人类的健康及动物福利。朊蛋白基因的ORF氨基酸的多态性(Prnp)与TSE的潜伏期、遗传易感性及种间屏障有关。在本研究中,首次对蒙原羚(Procapra gutturosa)朊蛋白基因的ORF进行全序列分析和多态性研究。研究结果发现,26只蒙原羚Prnp高度同源,与汤氏瞪羚(Eudorcas thomsonii)、印度羚(Antilope cervicapra)、牛(Bos taurus)的SNP的同源性较近,分别为100%、100%和98.5%,然而,斑纹角马(Connochaetes taurinus)、欧洲狍(Capreolus capreolus)和绵羊(Ovis aries)与八肽重复区的缺失相关,蒙原羚与它们的同源性分别为99.3%、99.3%和98.9%。蒙原羚在6个位点发生氨基酸的置换分别为119(N→S),143(S→G),160(Y→H),172(V→A),182(N→S)和221(V→A)。在N端的R5(87-94)缺失1个八肽重复区。蒙原羚Prnp序列的特殊性可能影响分子间的相互作用和TSE种间屏障起关键的作用。

Prion diseases are a group of human and animal neurodegenerative conditions that are caused by the deposition of an abnormal isoform prion protein （ PrPso） encoded by a single copy prion protein gene （Prnp）. In sheep, genetic variations of Prnp were found to be associated with the incubation period, susceptibility, and species barrier to the scrapie disease. We investigated the sequence and polymorphisms of the prion protein gene of Mongolian gazelles （gPrnp）. gPrnp gene sequence analysis of blood samples from 26 Mongolian gazelles showed high identity within species. The gPrnp gene was closely related to the Prnp genes of Thomson＇s gazelle, blackbuck, and cattle with 100, 100, and 98. 5% identity, respectively. The gPrnp gene with a deletion was closely related to the Prnp genes of wildebeest, Western roe deer, and sheep with 99. 3, 99. 3, and 98. 9% identity, respectively. Polymorphisms of the open reading frame of Prnp as amino acid substitutions were detected at codons 119 （ N→S ）, 143 （ S→G ） or 160 （ Y→H ）, 172 （ V→A）, 182 （N →S）and 221 （V→A）. There was also deletion of one octapeptide repeat at the N -termi- nal octapeptide repeat region. The polymorphisms of gPrnp will assist the study of prion disease pathogenesis, resistance, and cross species transmission.