Molecular cloning and characterization of the α-chain gene of goose immunoglobulin heavy chain.

A novel gene encoding the α-chain of goose immunoglobulin heavy-chain (Igα) was cloned by reverse transcription-PCR. The cDNA had 1,760 bp and encompassed a partial V-D-J region of the heavy chain, a constant region (Cα) and 3'-untranslated region of α-chain. The Cα gene contains four constant region domains (CH1-CH4). Phylogenetic analysis indicated that goose IgCα has a close genetic relationship with duck, ostrich and chicken IgCα. Three-dimensional modeling and glycosylation analysis revealed the goose Igα is consistent with the characterization of immunoglobulin. Western blotting suggested the goose IgCα has the same antigenicity to natural IgA. In general, the identification of goose immunoglobulin not only provides insights into the evolution of the Ig heavy-chain gene family, but may also benefit future studies of the avian immune system.