Production of mouse granulocyte-macrophage colony-stimulating factor by gateway technology and transgenic rice cell culture

To establish a production platform for recombinant proteins in rice suspension cells, we first constructed a Gateway‐compatible binary T‐DNA destination vector. It provided a reliable and effective method for the rapid directional cloning of target genes into plant cells through Agrobacterium‐mediated transformation. We used the approach to produce mouse granulocyte‐macrophage colony‐stimulating factor (mGM‐CSF) in a rice suspension cell system. The promoter for the αAmy3 amylase gene, which is induced strongly by sugar depletion, drove the expression of mGM‐CSF. The resulting recombinant protein was fused with the αAmy3 signal peptide and was secreted into the culture medium. The production of rice‐derived mGM‐CSF (rmGM‐CSF) was scaled up successfully in a 2‐L bioreactor, in which the highest yield of rmGM‐CSF was 24.6 mg/L. Due to post‐translational glycosylation, the molecular weight of rmGM‐CSF was larger than that of recombinant mGM‐CSF produced in Escherichia coli. The rmGM‐CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell line, NSF‐60. Biotechnol. Bioeng. 2012; 109:1239–1247. © 2011 Wiley Periodicals, Inc. The authors constructed a Gateway‐compatible binary T‐DNA destination vector for the easy establishment of a production platform for recombinant proteins in rice suspension cells. Here, the 2‐L bioreactor was used for the production of recombinant mouse granulocyte‐macrophage colony‐stimulating factor (mGM‐CSF), a cytokine that functions in the growth of white blood cells, in cultured rice suspension cells. The recombinant mGM‐CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell.