Cloning and Optimization of Intracellular Expression of Human Interferon β-1a in Pichia pastoris GS115

Interferon-beta (IFN-β) is a cytokine with a wide range of biological and pharmaceutical applications, including multiple sclerosis (MS), cancer, some autoimmune disorders, and viral infectious diseases. Thus, many studies have been performed to develop novel strategies for the high-yield production of functional IFN-β in a cost-effective approach. Here, we aimed to improve the intracellular expression of IFN-β-1a in Pichia pastoris.

The gene of IFN-β-1a was successfully sub-cloned into the pPICZA vector. The recombinant vector was transfected to P. pastoris GS115 cells by electroporation. After screening positive P. pastoris transformants, the expression of IFN-β-1a was evaluated and the cultivation conditions, including temperature, time of incubation, and methanol concentration, were optimized. The protein expression levels were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

The double digestion with EcoRI and XhoI restriction enzymes and sequence analysis confirmed the correct sub-cloning of the IFN-β-1a gene into pPICZA. SDS-PAGE analysis showed that the highest level of IFN-β-1a (25 mg per 1 L of yeast culture) was produced with 2% methanol at 28°C after 72 h incubation.

Optimization of cultivation conditions for intracellular expression of IFN-β-1a was successfully performed. This approach can be generally applied to improve the production yield and quality of other recombinant proteins in P. pastoris.