Secretory Expression of Bovine IL-2 Gene in Pichia pastoris

The bovine Interleukin-2 gene was inserted into the Pichia pastoris expression vector pPICZ#alpha#A which contains AOXI promoter and #alpha#-factor signal sequence. The recombinant plasmid of BoIL-2pPICZ#alpha#A was linearnized by Sac I and transformed into X-33 and KM71H by electroporation. The recombinant Pichia strains. identified by PCR and Zeocin resistance were cultured and induced with methanol. SDS-PAGE analysis and Western blot showed BoIL-2 was expressed in a fused protein with the #alpha#-factor signal peptide but failed to secrete into medium. Effect of signal peptide and prefer codon on efficiency of secretory expression was also discussed in detail.