Expression of mouse interleukin 4 receptor antagonist with Bac-to-Bac baculovirus expression system

Objective To express the mouse interleukin 4 receptor antagonist(mIL-4RA)protein with Bac-to-Bac baculovirus expression system.Methods mIL-4RA(C118 deletion)cDNA was obtained by polymerase chain reaction(PCR),and subcloned into the baculovirus transfer vector pFastBacHTB.Then the pFastBacHTB was transformed into competent DH10BacTM E.coli cells.The transposition was occurred between pFastBacHTB and bacmid and a recombinant bacmid was obtained.The positive clones were picked out and the recombinant bacmid was isolated,and then transfected into sf9 cells for producing recombinant baculovirus.The baculoviral stock was amplified and the mIL-4RA protein was expressed.Enzyme linked immunosorbent assay(ELISA)was used to identify and quantify the production of protein.Results The presence of mIL-4RA cDNA in the recombinant bacmid was verified by PCR and gene sequencing.The cytopathic effect(CPE)displayed by the infected sf9 cells assumed that the transfection was successful.The concentration of the mIL-4RA protein in the culture media determined by ELISA was(1.15±0.12)ng/mL.Conclusion The mIL-4RA protein is expressed successfully by Bac-to-Bac baculovirus expression system,which may lay foundation for further studying on biological activities and functions of the protein.Meanwhile,the research could provide technique support for eukaryotic expression of other proteins.