[Expression of TMP Fc in Pichia pastoris and identification of its biological activity]

The DNA coding for the fusion protein of thromobopoietin mimetic peptide (TMP) and human IgG1 Fc fragment was amplified from recombinant plasmid pET28a/TMPFc, inserted into pPICZalphaA and transformed into Pichia pastoris using electroporation. The recombinants of correct phenotype were identified after screening on MDH and MMH culture medium. The fusion gene was verified with PCR and western blot. MTT method was used to test the activity of TMPFc in promoting the growth of Ba/ F3-mpl cell. The TMPFc with a 64 000 molecular weight was a secretary protein in the system and its expression amounted to 65% of the total protein in the medium supernatant. The TMPFc showed a promotive effect on the growth of Ba/F3-mpl in vitro. A significant portion of the secretary protein existed as dimer, which provided material for studying the dimer in future.