Comparative analysis of cloned cDNAs encoding Chinese yellow cattle and Gansu black swine integrin receptors for foot-and-mouth disease virus.

To analyze foot-and-mouth disease virus tropism and host range with respect to the integrin receptor, we cloned cDNAs encoding the integrin αν, β1, β3, β6 and β8 subunits from Chinese yellow cattle and Gansu black swine and carried out comparative analysis of their molecular characteristics. The lengths of the mature proteins and the functional domains of the four integrin β subunits were the same between bovine and swine; however, the number of putative N-linked glycosylation sites and cysteine residues and their arrangement varied. Homology analysis of the nucleotide and amino acid sequences showed that FMDV integrin receptors of Chinese yellow cattle and Gansu black swine are highly conserved. Phylogenetic analysis showed that all FMDV integrin receptor subunits of cattle and swine are clustered into the Artiodactyla group; however, Chinese yellow cattle are phylogenetically closer to sheep than to Gansu black swine. We postulate that the host tropism of FMDV may, in part, be related to the divergence of integrin subunits among different species.