Objective: To express recombinant human platelet factor 4 (PF4) in methanol yeast.
Methods: PF4 cDNA amplified by PCR was cloned into the mating factor alpha (MFalpha) signal sequence, downstream the alcohol oxidase 1 (AOX 1) promoter of the pPIC9 vector. The reconstructed vector was subsequently integrated into the methanol yeast P. pastoris strain GS115. The highly expressing strain was selected and the protein sequences and their biological activities were assayed.
Results: The amino acid sequence of rhPF4 was the same as that of natural one. The rhPF4 can neutralize the anticoagulation effect of heparin in a dose-dependent manner.
Conclusion: The amount of rhPF4 expressed in methanol yeast meets well the scale for manufacturing. The biological activities of the rhPF4 were the same as that of natural PF4.