Expression of HIV-2 gp105-gag truncated gene in Pichia pastoris

Objective: To carry out the secretive express of HIV-2_ROD tgp105-gag protein and the optimization of expression conditions. Methods: HIV-2 gp105 truncated gen (tgp105) was obtained by PCR amplification and was cloned into a secreting expression vector pPIC-9. Recombinant expression vector pPIC9 tgp105-gag was constructed by inserting HIV-2 gag into pPIC9 tgp105 recombinant plasmid, then transformed into GS115 cells. Positive clones were selected with MD/MM plates and confirmed by PCR. Several clones were incubated in BMGY media and induced by 0.5% methanol in BMMY media. The expression product HIV-2 tgp105-gag protein was analyzed by SDS-PAGE and confirmed by Western blot. Results: The tgp105-gag protein was secreted into media. The molecular weight of the expressed protein, as analyzed by SDS-PAGE, was 140kD. The Western blot result showed that the expressed protein could be detected by HIV-2 specific antibody. Conclusion: The recombinant plasmid HIV-2_ROD tgp105-gag was successfully expressed in Pichia pastoris and the expressed protein has a good antigen specificity.