Construction of yeast Pichia pastoris expressing secreted mini-proinsulin into culture

Abstract

Diabetes is one of the diseases, which have recently gained significant attention. In order to produce the recombinant insulin for treating diabetics, we have cloned and expressed a mini-proinsulin in Pichia pastoris. The DNA fragment containing a gene encoding the fusion protein of miniproinsulin-6xhis was cloned into the integrative plasmid pPICZαA resulting in pPICZαA/h-mpi to construct the strain P. pastoris GS115::h-mpi expressing the recombinant MPI as secreted protein into culture. Phenotype and genotype of P. pastoris GS115::h-mpi were confirmed by PCR and restriction pattern. MPI was expressed as a fusion protein with 6xhis tag by supplementing methanol at a final concentration of 0.5% in BMMY culture medium for 96 hours after inducing.