• Cloning and expression of human interferon gamma in Escherichia coli
  • Reyhaneh Sajed,1 Saeed Aminzadeh,2 Ali-Asghar Karkhanei,3,*
    1. Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
    2. Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
    3. Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.


  • Introduction: Human interferon gamma (hIFN-γ) is a glycoprotein that is produced by normal T and killer cells. hIFN-γ is often used in research due to its many roles in the immune system, such as antiviral activity, antitumor activity, and control of cellular apoptosis. The production of hIFN-γ in bacterial cells is associated with the formation of insoluble inclusion bodies. To overcome this problem, a protein fusion method was used.
  • Methods: In this study, based on the SUMO fusion system, the hIFN-γ along with the sumo tag was successfully cloned in the pET21b vector and expressed in Escherichia coli. The expression of hIFN-γ was induced by adding IPTG to a final concentration of 0.5 mM. at 24°C. Finally, the hIFN-γ was purified with a nickel column and treated with SUMO protease enzyme, in order to separate the SUMO part from the hIFN-γ protein.
  • Results: SDS-PAGE showed a protein band of about 35 kDa including sumo protein and hIFN-γ. Subsequently, the hybrid protein was treated with SUMO enzyme and hIFN-γ with a molecular weight of about 17 kDa purified.
  • Conclusion: SUMO fusion enhances protein expression, solubility, and purification of protein in E. coli. Also, SUMO fusion enhances the level of protein production. We by using this method produce the soluble hIFN-γ in E. coli.
  • Keywords: human interferon gamma, SUMO tag, solubility, Escherichia coli, purification