偶蹄家畜FMDV受体通用亚基αv基因的分子特征及其进化关系

Molecular Characteristics and Phylogenetic Relationships of cDNA Encoding αv Subunit as FMDV Receptor in Cloven-hoofed Domestic Animals

已发现至少有αvβ1、αvβ3、αvβ6、αvβ8 4种整联蛋白是FMDV的细胞受体,αv是4种受体的通用亚基。本试验中从FMDV实验感染猪和牛、健康羊和双峰驼等的肺组织中克隆到了受体通用亚基αv基因,并对其序列进行了比较和进化关系分析。结果显示,羊、牛、猪、双峰驼的αv亚基基因的编码区分别含有3147、3147、3141、3165个核苷酸,分别编码1048、1048、1046、1054个氨基酸,信号肽均由氨基端30个氨基酸组成,跨膜区、胞浆区均分别由29、32个氨基酸组成;胞外区分别由957、957、955、963个氨基酸组成。羊、牛、猪、双峰驼αv亚基基因在Gen-Bank中的登录号分别为EU367989、DQ871215、EF474019、EU367990。同源性分析表明,信号肽变异最大,胞外区次之,跨膜区和胞浆区比较保守;进化树表明,与灵长类、啮齿类、奇蹄类、禽类、食肉类等口蹄疫非易感物种相比,口蹄疫易感动物羊、双峰驼、猪、牛等偶蹄家畜αv亚基的亲缘关系较近,处于同一进化分支。这表明受体αv亚基可能与FMDV的宿主范围和组织嗜性有关。

Foot-and-mouth disease virus（FMDV）has been showed at least to use four integrins, αvβ1, αvβ3, αvβ6 and αvβ8 as receptors to initiate infection. In this study, the integrin αv genes were cloned from the lung tissue of cattle and pig, both infected experimently with FMDV, healthy sheep and Bactrian camel by RT-PCR. The nucleotide and predicted amino acid sequences of the αv genes of sheep, cattle, pig, Bactrian camel, human, dog, horse, chimpanzee, rhesus monkey, chicken, and mouse were analyzed. The ORF of integrin αv cDNA of sheep, cattle, pig, Bactrian camel consists of 3 147 nt, 3 147 nt, 3 141 nt, 3 165 nt, encoding a polypeptide of 1 048 aa,1 048aa, 1 046 aa, 1 054 aa, respectively. The putative signal peptide, transmembrane domain and cytoplasmic domain consists of 30, 29, 32 residues, respectively. The ectodomain of integrin αv contains 957 aa, 957 aa, 955 aa, 963 aa in sheep, cattle, pig, Bactrian camel, resoectively. The homology analysis showed that the signal peptides exhibit the lowest conservation, and the transmembrane domain and cytoplasmic domain exhibit the highest degree of conservation, and the degree of similarity was somewhat higher for ectodomain. Phylogenetic analysis revealed that integrin αvs of sheep, cattle, pig, Bactrian camel belonged to the same branch, suggesting that they had a close genetic relationship. It is possible that host and tissue tropism of FMDV may related to divergence in αv subunit among different species.