Efficient Secretion of Recombinant Proteins from Rice Suspension-Cultured Cells Modulated by the Choice of Signal Peptide

Abstract

Plant-based expression systems have emerged as a competitive platform in the large-scale production of recombinant proteins. By adding a signal peptide, αAmy3sp, the desired recombinant proteins can be secreted outside transgenic rice cells, making them easy to harvest. In this work, to improve the secretion efficiency of recombinant proteins in rice expression systems, various signal peptides including αAmy3sp, CIN1sp, and 33KDsp have been fused to the N-terminus of green fluorescent protein (GFP) and introduced into rice cells to explore the efficiency of secretion of foreign proteins. 33KDsp had better efficiency than αAmy3sp and CIN1sp for the secretion of GFP from calli and suspension-cultured cells. 33KDsp was further applied for the secretion of mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) from transgenic rice suspension-cultured cells; approximately 76%–92% of total rice-derived mGM-CSF (rmGM-CSF) was detected in the culture medium. The rmGM-CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell line, NSF-60. The extracellular yield of rmGM-CSF reached 31.7 mg/L. Our study indicates that 33KDsp is better at promoting the secretion of recombinant proteins in rice suspension-cultured cell systems than the commonly used αAmy3sp.

Purification, characterization, and N‐glycosylation of recombinant butyrylcholinesterase from transgenic rice cell suspension cultures

“…This may be explained by the fact that Brazzolotto et al loaded a cell culture medium containing secreted BChE to the resin, which has a lower concentration of other non‐target host cell proteins compared with a whole cell extract. As previously reported, the majority of rrBChE is found associated with the biomass rather than in the culture media, likely due to the protein's large size (Corbin et al, ; Huang et al, ).…”

Expression of Recombinant Human Octamer-Binding Transcription Factor 4 in Rice Suspension Cells

“…Transformation of rice was performed as described previously with a slight modification [ 44 ]. The expression vector, pAAmy3-Oct4, carrying the αAmy3 promoter–signal peptide–Oct4 cassette was introduced into Agrobacterium tumefaciens strain EHA105 by electroporation.…”

Genetic engineering of transitory starch accumulation by knockdown of OsSEX4 in rice plants for enhanced bioethanol production

“…Seeds were germinated and screened on 1/2 MS medium containing 25 mg/L hygromycin to select stable transformed plants containing T‐DNA derived from pMDC32 and pMDC32‐OsSEX4, respectively. For transformation of rice, pAUSEX4i plasmid was introduced into Agrobacterium tumefaciens strain EHA105 by electroporation, and rice plants were transformed as described previously (Huang et al, 2015). Briefly, embryogenic calli were incubated with the Agrobacterium for 20–25 min.…”