Sheep (Ovis aries) integrins alphavbeta1 and alphavbeta6 related to foot-and-mouth disease virus infection: molecular cloning, sequence analysis and comparison with homologues.

Four members of the alphav integrin family of cellular receptors, alphavbeta1, alphavbeta3, alphavbeta6, and alphavbeta8, have been identified as receptors for foot-and-mouth disease virus (FMDV) in vitro, and integrins are believed to be the receptors used to target epithelial cells in the infected animals. To analyse roles of the alphav integrins from a susceptible species as viral receptors, we have cloned sheep alphav, beta1, and beta6 integrin cDNAs and compared them to those of other species. The coding sequences for sheep integrin alphav, beta1, and beta6 were found to be 3147, 2397, and 2364 nuclotides in length, encoding 1048, 798, and 787 amino acids, respectively. The sheep alphav, beta1, and beta6 subunits share many structural features including ligand binding domain and cysteine-rich region with homologues of other species. Phylogenetic trees and similarity analyses showed the close relationship of integrin genes among sheep, pigs, cattle and Bactrian camels that are susceptible to FMDV infection, which were distinct from the order Rodentia, Primates, Perissodactyla, Carnivora, Galliformes. We postulate that host tropism of FMDV may be related to divergence in integrin subunits among different species.