High level secretory expression of human oncostatin M in Pichia pastoris

Objective To explore the method of secretory expression of recombinant human oncostatin M (rhOSM) in Pichia pastoris. Methods The human embryonic genomic DNA was used as templet to obtain the sequence of mature hOSM gene by PCR,the expression vector of Pichia pastoris of pPICZαC-hOSM was constructed. The recombinant plasmid was transformed into Pichia pastoris X-33 via electroporation.The transformed positive strains were screened by PCR. The supernatant were analyzed by SDS-PAGE and Western blotting to screen Pichia pastoris engineer bacteria with highly effective expression of rhOSM. Results The mature hOSM DNA was obtained by PCR. SDS-PAGE and Western blotting analysis showed there was rhOSM in the culture supernatant induced by methanol with 28 000 of molecular weight.Conclusion Pichia pastoris can express rhOSM efficiently,the expression level of rhOSM reaches at 45 mg·L-1 in flask scale.