中国生物工程杂志

cDNA encoding goose IL-2 (goIL-2) was cloned from Con A-stimulated goose SMC using oligonucleotide primers based on the conserved sequence of duck IL-2 (duIL-2), chicken IL2 (chIL-2) and turkey IL-2 (TuIL-2). Sequencing results showed that the goIL-2 nucleotide sequence was 768 bp in length, encoding a polypeptide of 141 amino acid residues. The predicted nucleic acid and amino acid sequences of goIL-2 were of 90.1% and 83.6% identical to duIL-2, 69.7%-75% and 61.0%-63.1% to chIL-2, tuIL-2 and quail IL-2, 25%-30% and 14%-17% with mammalian IL-2s, respectively. Amino acid sequence analysis showed that the predicted protein had a leader sequence composed of 21 amino acids, and four conserved cysteines allowing the formation of two intrachain disulfide bonds. GoIL-2 mRNA was detectable using RT-PCR assay in goose splenic mononuclear cells from 2 h to 24 h after stimulation. Three-dimensional structure prediction indicated that the mature goose IL-2 protein contained A, B, C and D four α-helix bundle structures and two β-sheets. Phylogenetic analysis showed that the goIL-2 had close relationship with duIL-2 and had distant relationship with tuIL-2.