Production of therapeutic proteins in the chloroplast of Chlamydomonas reinhardtii

Abstract

Chloroplast transformation in the photosynthetic alga Chlamydomonas reinhardtii has been used to explore the potential to use it as an inexpensive and easily scalable system for the production of therapeutic recombinant proteins. Diverse proteins, such as bacterial and viral antigens, antibodies and, immunotoxins have been successfully expressed in the chloroplast using endogenous and chimeric promoter sequences. In some cases, proteins have accumulated to high level, demonstrating that this technology could compete with current production platforms. This review focuses on the works that have engineered the chloroplast of C. reinhardtii with the aim of producing recombinant proteins intended for therapeutical use in humans or animals.

Keywords: Chlamydomonas; Chloroplast transformation; Recombinant therapeutic proteins.

Figure 1

Chloroplast transformation in Chlamydomonas reinhardtii . a) Introduction of foreign DNA material into the chloroplast of C. reinhardtii is carried out using a particle bombardment device. The device uses helium gas to accelerate particles towards algae placed at the interior of a vacuum chamber. b) Gold or tungsten particles are coated with a plasmid carrying the genes of interest (in this case the green fluorescence protein GFP) and when accelerated penetrate the cells placed on top of selection medium. After a few weeks, transformed cells proliferate in the presence of a selection antibiotic. c) When the plasmid carrying the genes reaches de chloroplast, genes integrate into the plastid genome by homologous recombination between regions present in the plasmid (LB and RB) and in the chloroplast genome (CpDNA).