Cloning and sequencing of a cDNA encoding the bovine FcR γ chain

Phagocytic cells of the immune system express specific receptors for the Fc region of immunoglobulins (FcRs). In humans, most FcRs for IgG (FcγR), IgA (FcαR) and IgE (FcεR) consist of an immunoglobulin (Ig) -binding subunit associated with a specialized signaling molecule, the FcR γ chain. The FcR γ chain is crucial for the transmission of intracellular signals following receptor ligation. In cattle, however, although four distinct complimentary DNAs (cDNAs) encoding IgG-binding subunits have been described (corresponding to bovine FcγRI, FcγRII, FcγRIII, and Fcγ2R), virtually, nothing is known about signal transduction via bovine FcRs. Therefore, in this study, a cDNA encoding the bovine FcR γ chain was cloned. The cDNA is 258 base pairs long and encodes a protein of 85 amino-acids. The mature protein shows high homology with the FcR γ chains from several other species. Interestingly, the cytoplasmic domain of the bovine FcR γ chain is one amino-acid shorter than those previously described. Cloning of a cDNA encoding, the bovine FcR γ chain will allow for a better understanding of signal transduction processes triggered by bovine FcRs.