Cloning and expression of IFN-α gene from Huiyang chickens and studies on the antiviral activity, circular dichroic analysis of its recombinant protein

IFN-α is a cytokine with high antiviral activity. Huiyang IFN-α was cloned from liver genomic DNA. The homoligies were from 96.9%～97.9% between Huiyang chicken IFN-α and IFN-α s on Genbank, indicating this IFN-α gene was a new subtype. The recombinant plasmid IFN-α/pPICZαA confirmed by enzyme digestion, PCR and sequencing was transformed into Pichia pastoris GS115. After 1% methanol induction, SDS-PAGE analysis of the culture supernatant of recombinant yeast strains indicated that the yield of recombinant IFN-α was 0.307 mg/ml and the molecular weight was about 35 kD. The recombinant IFN-α expressed by Pichia pastoris showed antiviral activity of 3.2×106 U/mg in CEF/VSV, which was higher than that from E.Coli. The secondary structure of recombinant IFN-γ analyzed by Circular Dichroism showed that the contents of this protein were: 53.2% α-helix;3.1% β sheet, 10.6% turn; 33.1% random, which showed it was a tipical helical protein. This paper reported that recombinant IFN-α with high antiviral activity was highly produced in Pichia pastoris and first confirmed that chicken IFN-α was a helical protein which was similar to IFN-α of mammals.