Genetic characterization and ligand specificity of the ovine Fc gamma receptor I (ovFcγRІ)

Receptors for the Fc region of IgG (FcγRs) play a critical role in the immune system and host protection against infection. In this study, we describe the cloning, mRNA expression and IgG subclass specificity of ovine Fc gamma receptor I (ovFcγRI). The ovFcγRI cDNA contains a 1047 bp open-reading frame, and is predicted to encode a 349 amino acid trans-membrane glycoprotein composed of three immunoglobulin-like domains, a trans-membrane region and a short cytoplasmic tail. The overall identity of the ovine FcγRI to its cattle, human and mouse counterparts at the level of the amino acid sequence was 92%, 61% and 54%, respectively. Rosetting analysis shows that COS-7 cells were transfected with an expressional vector carrying the cDNA open-reading frame of ovFcγRI and expressed this receptor on the surface. Identification of ovine FcγRI will aid in the understanding of molecular basis of the ovine immune system and further studies of the receptor function.