Cloning,expression, and activity determination of Shaoxing duck IFN-α gene

AbstrcatUsing PCR method,Shaoxing duck interferon-alpha gene (SX-DuIFN-α) was amplified from the genomic DNA of Shaoxing duck liver and cloned into vector pUC18. After sequencing, the gene of mature SX-DuIFN-α protein was sub-cloned into expression vector pET-28α (+) and expressed in E.coli BL21-plysS. After renaturation, the antiviral activity of the expression product was determined. The results of sequencing showed that sxDuIFN-α consisted of 576 nucleotides, encoding 191 amino acids. The homologies of the sxDuIFN-α, DuIFN-α in GenBank and BDIFN-α nucleotide sequences were 99.3% and 99.1%, respectively, and amino acid homology was 97.9% among them. By induction with IPTG, the expression vector pET-28α (+) containing sxDuIFN-α gene had expressed DuIFN-α with relative molecular weight of 20.7 kD.This expression product was verified to be of high antiviral activity against VSV and attenuated duck plague virus by inhibiting the cytopatic effect.