Molecular cloning, expression and characterization of an interleukin 27 p28 homolog in pig (Sus scrofa)

IL-27 is the newest member of the IL-12 cytokine family and plays an important role in the immune regulation. It is composed of two subunits, p28 and EBV-induced gene 3(EBI3). Although human and mouse IL-27 p28 genes have been cloned, pig IL-27 p28 gene has not ever been reported. In the present study, we have cloned and characterized the full-length cDNA of IL-27 p28 from pig. The open reading frame of pig IL-27 p28 gene is 720 bp, which encodes a protein of 239 amino acids with a predicted molecular mass of 26.6 kDa. The deduced amino acid sequence of pig IL-27 p28 showed a high degree of homology to human (63%) and mouse (58%). It was a 4-helix cytokine and belonged to 4-helix cytokine superfamily. Pig IL-27 p28 has one transmembrane region, one signal peptide, and one N-glycosylation site, two Protein kinase C phosphorylation sites, three Casein kinase II phosphorylation sites and one N-myristoylation site. For the expression of pig IL-27 p28 protein in a eukaryotic expression system the recombinant plasmid was constructed. The expression of pig IL-27 p28 in mammalian cells were confirmed by flow cytometry analysis, immunofluorescence and Western blot. The analysis also confirmed a cross reactivity with anti-mouse IL-27 p28 antibody. This is the first report of cloning and characterization of IL-27 p28 in pig.