Knockdown expression of a MYB-related transcription factor gene, OsMYBS2, enhances production of recombinant proteins in rice suspension cells

• Published in: Plant methods Vol. 17; no. 1; pp. 1 - 99
• Main Authors: Sinaga, Desyanti Saulina, Ho, Shin-Lon, Lu, Chung-An, Yu, Su-May, Huang, Li-Fen
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 25.09.2021; BioMed Central; BMC
• Subjects: Binding sites; Cell culture; Colony-stimulating factor; Genetic aspects; Genetic engineering; Genetically altered foods; Granulocyte-macrophage colony-stimulating factor; Methods; Mouse GM-CSF; OsMYBS2; Peptides; Physiological aspects; Plant cells; Plant reproduction; Production processes; Proteins; Recombinant protein; Recombinant proteins; Rice; Rice suspension cells; Seeds; Sucrose; Sugar; Transcription factors; Transgenic plants; αAmy3 promoter; Taiwan
• ISSN: 1746-4811; 1746-4811
• DOI: 10.1186/s13007-021-00799-2

Transgenic plant suspension cells show economic potential for the production of valuable bioproducts. The sugar starvation-inducible rice [alpha]Amy3 promoter, together with its signal peptide, is widely applied to produce recombinant proteins in rice suspension cells. The OsMYBS2 transcription factor was shown recently to reduce activation of the [alpha]Amy3 promoter by competing for the binding site of the TA box of the [alpha]Amy3 promoter with the potent OsMYBS1 activator. In this study, rice suspension cells were genetically engineered to silence OsMYBS2 to enhance the production of recombinant proteins. The mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) gene was controlled by the [alpha]Amy3 promoter and expressed in OsMYBS2-silenced transgenic rice suspension cells. Transcript levels of the endogenous [alpha]Amy3 and the transgene mGM-CSF were increased in the OsMYBS2-silenced suspension cells. The highest yield of recombinant mGM-CSF protein attained in the OsMYBS2-silenced transgenic suspension cells was 69.8 [micro]g/mL, which is 2.5-fold that of non-silenced control cells. The yield of recombinant mGM-CSF was further increased to 118.8 [micro]g/mL in cultured cells derived from homozygous F.sub.5 seeds, which was 5.1 times higher than that of the control suspension cell line. Our results demonstrate that knockdown of the transcription factor gene OsMYBS2 increased the activity of the [alpha]Amy3 promoter and improved the yield of recombinant proteins secreted in rice cell suspension cultures.