Expression of Goose Interleukin-2 gene in Escherichia coli and Isolation of Its Soluble Monomer
鹅IL-2基因在大肠杆菌中的表达及其可溶性单体的分离

Recombinant expression plasmid of pET-28a (+)-goIL-2 was constructed by inserting the goose IL-2 gene without the signal peptide sequence into the prokaryotic expression vector pET-28a (+), and transformed into the bacterial competent E. coli BL21 (DE3) cells for expression. After IPTG induction, an expected protein band with molecular weight of 15.0 kD was observed on SDS-PAGE gel, recognized by monoclonal antibody against goose IL-2 in western-blotting assay. In the pET-28a (+) expression system, much of the recombinant goose IL-2 (rgoIL-2) was found in inclusion bodies with a portion of soluble protein. The monomer and multimers of soluble goose interleukin 2 proteins were observed in native electrophoresis. The rgoIL-2 proteins were purified by Ni-NTA column under a native condition. The rgoIL-2 soluble protein monomer was isolated by a quick protein isolation and purification system of ?KTA FPLC and identified by native PAGE. Bioactivity analysis showed that the rgoIL-2 monomer stimulated the proliferation of goose lymphocytes in vitro. This will establish a basis for further study about the biological function and clinical application of goose IL-2.