Tissue specific expression of human calcitonin gene in potato tubers by an organ specific promoter

Document Type : Research Paper


1 Biotechnology Department, Iranian Research Organization for Science and Technology, P.O. Box 15815/3538, Tehran, I.R. Iran.

2 Faculty of Agriculture, University of Lorestan, Khorramabad, I.R. Iran.


To increase the production level of heterologous proteins in plants, strategies such as choice of stronger
promoters, optimization of codon usage and specific localization of foreign proteins are of major concern.
Calcitonin (CT), a 32 amino acid polypeptide is a powerful and specific inhibitor of bone resorption and is
used to treat several human diseases. Calcitonin activity is not species-specific which make it possible to
produce in various animal sources, however, antibody formation in the prolonged application of animal CT
leads to gradual decrease or loss of activity. That is why the long term treatment of human patients with CT
requires homologous calcitonin. In this study, a human calcitonin (hCT) gene, driven by two different promoters (granule bound starch synthase I and Cauliflower mosaic virus 35S) was expressed in potato plants, using Agrobacterium-mediated transformation. Molecular analysis, including PCR, RT-PCR, Northern
dot blot hybridizations showed that hCT could be successfully transcribed in transgenic potato plants. The
immunoassay results showed that tissue specific expression in potato, led to almost five-fold more hCT
accumulation when compared to the constitutively expression in all plant tissues.