| Introduction: Attributable to some critical features
especially the similarity of the protein synthesis
machinery between humans and microalgae, these
microorganisms can be utilized for the expression
of many recombinant proteins. However, low and
unstable gene expression levels prevent the further
development of microalgae biotechnology towards
protein production.
Methods: Here, we designed a novel “Gained
Agrobacterium-2A plasmid for microalgae expression”
(named GAME plasmid) for the production of the
human interleukin-2 using three model microalgae,
including Chlamydomonas reinhardtii, Chlorella
vulgaris, and Dunaliella salina. The GAME plasmid
harbors a native chimeric hsp70/Int-1/rbcS2 promoter, the microalgae specific Kozak sequence, a
novel hybrid 2A peptide, and Int-1 and Int-3 of the rbcS2 gene in its expression cassette.
Results: The obtained data confirmed that the GAME plasmid can transform the microalgae
with high transformation frequency. Molecular and proteomic analyses revealed the stable
and robust production of the hIL-2 by the GAME plasmid in the microalgae. According to the
densimetric analysis, the microalgae can accumulate the produced protein about 0.94% of the
total soluble protein content. The ELISA data confirmed that the produced hIL-2 possesses the
same conformation pattern with the acceptable biological activity found naturally in humans.
Conclusion: Most therapeutic proteins need post-translational modifications for their correct
conformation, biological function, and half-life. Accordingly, microalgae could be considered as
a cost-effective and more powerful platform for the production of a wide range of recombinant
proteins such as antibodies, enzymes, hormones, and vaccines. |