Secretory expression of recombinant human calciton in Chlamydomonas reinhardtii

Introduction: Calctonin is a small pe ptide hormone that is produced by parafollicular thyroid cells in human and plays a role in metabolism regulation of calcium and phosphorous. Calcitonin usage is in treatment of calcium related disorders. Calcitonin major structural feature is C-terminus amidation, so recombinant calcitonin produced by prokaryoti c or yeat hosts needs to beamidated and bio active recombinant calcitonin is produced by an imal cell culture. Microalgae recently attrac ted attention for their ability in recombinant protein expression. Microalgae can provide all desired characteristics for recombinant protein expression. Chlamydomonas reinhardtii is the well known algal species that is use d as the host for production of recombinant compounds. In the present study, the a bility of Chlamydomonas reinharditii for sec retory production of recombinant human calcitonin is assayed. Methods: Calcitonin coding was o ptimized for expression in C. reinharditii and cloned downstream of the secretory signal peptide pchlamy 4 vector. The combinant plasmid was transformed to cw15 strain (cell wall deficient) by electroporation. Primary screen ing was performed by colony PCR and selected strains were cultivated in higher volumes. In regard to secretory production, culture media was collected and assayed by ELISA, sDS-P age and WESTERN blot. Results and discussion: One recombinant strain among four strains could produce about 1 pg calcitonin mL-1. The results show that the strategy for secretory production of recombinant calcitonin was prosperous and can be used in future studies especially for analysis of amidation.