title: High-yield production of authentic human growth hormone using a plant virus-based expression system.
abstract: We describe here a high-yield transient expression system for the production of human growth hormone (hGH, or somatotropin) in transfected Nicotiana benthamiana leaves. The system is based on a recently described plant virus-based modular expression vector [Gleba, Y., Marillonnet, S. and Klimyuk, V. (2004) Engineering viral expression vectors for plants: the 'full virus' and the 'deconstructed virus' strategies. Curr. Opin. Plant Biol. 7, 182-188; Marillonnet, S., Giritch, A., Gils, M., Kandzia, R., Klimyuk, V. and Gleba, Y. (2004) In planta engineering of viral RNA replicons: efficient assembly by recombination of DNA modules delivered by Agrobacterium. Proc. Natl. Acad. Sci. USA, 101, 6852-6857], and represents a simple and fast alternative to stable transformation. By using various combinations of provector modules, hGH was produced in three compartments of the cell: the apoplast, the chloroplast and the cytosol. We found that targeting to the apoplast provided the highest amount of correctly processed and biologically active hGH, with a yield of up to 10% of total soluble protein or 1 mg per gram of fresh weight leaf biomass. These results indicate that the use of viral vectors for high-yield production of human therapeutic proteins in plants by transient expression provides an attractive alternative to production protocols using standard expression vectors in transgenic or transplastomic plants.
authors.affiliation: Icon Genetics, Biozentrum Halle, Weinbergweg 22, D-06120 Halle, Saale, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Gils
authors.forename: Romy
authors.initials: R
authors.lastname: Kandzia
authors.forename: Sylvestre
authors.initials: S
authors.lastname: Marillonnet
authors.forename: Victor
authors.initials: V
authors.lastname: Klimyuk
authors.forename: Yuri
authors.initials: Y
authors.lastname: Gleba