Novel Mechanism Revealed for Increasing Recombinant Protein Yield in Tobacco

Overexpression of recombinant proteins is one of the strategies to obtain the desired phenotype in plants. Elastin-like polypeptides (ELP's) are synthetic biopolymers, and fused polypeptides have been shown to enhance the accumulation of different recombinant proteins in plants. Rita Menassa and colleagues of the Agriculture and Agri-Food Canada in London developed ELP tags fused to green fluorescent protein (GFP) and tested its utility and mechanism of action in increasing recombinant protein accumulation in the cytoplasm, chloroplast, apoplast and the endoplasmic reticulum (ER) of tobacco cells.  

Results showed that the ER was the only organelle that accumulated the elastin-like polypeptide and significantly enhanced recombinant fusion accumulation. In addition, a new type of protein body was found to be responsible for protecting the heterologous recombinant protein from degradation in the ER. These protein bodies express similarities in size and morphology to the prolamin-based protein bodies naturally found in plant seeds. The mammalian-derived ELP-GFP fusion protein seems to be protected by these protein bodies in plant cells during overexpression.  

For details see the abstract and short write up at: http://www.biomedcentral.com/1741-7007/7/48/abstract