E and M SARS‐CoV‐2 membrane protein expression and enrichment with plant lipid droplets

• Published in: Biotechnology journal 2024-01, Vol.19 (2), p.e2300512-n/a
• Main Authors: Gissot, Lionel, Fontaine, Florent, Kelemen, Zsolt, Dao, Ousmane, Bouchez, Isabelle, Deruyffelaere, Carine, Winkler, Michèle, Costa, Anais Da, Pierre, Fabienne, Meziadi, Chouaib, Faure, Jean‐Denis, Froissard, Marine
• Format: Article
• Language: English
• Subjects: camelina; colabfold; Goldenbraid; Life Sciences; lipid droplet; SARS‐CoV‐2; tobacco
• ISSN: 1860-6768; 1860-7314
• DOI: 10.1002/biot.202300512

Plants are gaining traction as a cost‐effective and scalable platform for producing recombinant proteins. However, expressing integral membrane proteins in plants is challenging due to their hydrophobic nature. In our study, we used transient and stable expression systems in Nicotiana benthamiana and Camelina sativa respectively to express SARS‐CoV‐2 E and M integral proteins, and target them to lipid droplets (LDs). LDs offer an ideal environment for folding hydrophobic proteins and aid in their purification through flotation. We tested various protein fusions with different linkers and tags and used three dimensional structure predictions to assess their effects. E and M mostly localized in the ER in N. benthamiana leaves but E could be targeted to LDs in oil accumulating tobacco when fused with oleosin, a LD integral protein. In Camelina sativa seeds, E and M were however found associated with purified LDs. By enhancing the accumulation of E and M within LDs through oleosin, we enriched these proteins in the purified floating fraction. This strategy provides an alternative approach for efficiently producing and purifying hydrophobic pharmaceuticals and vaccines using plant systems. Graphical and Lay Summary Plants are cost‐effective and scalable platforms for producing recombinant proteins but are limited in the case of hydrophobic membrane proteins. Transient and stable expression systems in Nicotiana benthamiana and Camelina sativa were used to express SARS‐CoV‐2 E and M integral proteins targeted to lipid droplets (LDs). This strategy provides an alternative approach for efficiently producing and purifying hydrophobic pharmaceutical and vaccine proteins using plant systems.