Cloning and sequencing of horse interferon-gamma cDNA

To facilitate the analysis of cytokine expression by horse lymphocytes, the complementary DNA (cDNA) for horse interferon-gamma (IFNG) was cloned and sequenced. Peripheral blood lymphocytes from a single horse were stimulated with Concavalin A and Phorbol Myristate Acetate for 6 h. The mRNA specific for IFNG was amplified by reverse transcription - polymerase chain reaction (RT-PCR), using primers from conserved regions present in humans, cattle, sheep, and pigs. Sequence information was obtained from four independent clones or RT-PCR products. The cDNA contains an open reading frame from nucleotides 65-562 encoding for a 166 amino acid protein including the 23 amino acid signal peptide and the 143 amino acids of the mature protein. The positions of the potential glycosylation sites are conserved among all species at the NH sub(2) terminus, and in the middle of the peptide sequence they are conserved among horse, cattle, sheep, and pig sequences.