Expression of Duck Interferon Alpha in BL21（DE3）plysS

To obtain the protein of duck interferon alpha and study its biological activities, the prokaryotic expression vector of DulFN-α was constructed and expressed in BL21 (DE3) plysS. Using PCR technique, the protein gene of DulFN-α was cloned from pMD-18-dulFN-α recombinant. The gene was then inserted to pGEM-T vector and identified by restriction endonuclease analysis and sequencing. DuIFN-α was ligated with the prokaryotic expres-sion vector of pET30a, then transformed into BL21 (DE3) plysS. The best inducing time and IPTG concentration for the expression of this recombinant protein was tested through the expression of the positive recombinant with different time span and different IPTG concentration. Lots of the protein of DuIFN-α were expressed in BL21(DE3)plysS with 1 mmol·L^-1 IPTG for 4 hours and its molecular weight for 34000.