Expression of erythropoietin in Indian tetraploid potato

With the advent of protein-based biotech drugs in the market, the quest for the “perfect” protein expression system, which is both economical and effective, has come into focus. Currently bacteria, yeast, insect cells, mammalian cells, transgenic animal and transgenic plants are widely used for the expression of therapeutic proteins. Among these, transgenic plants provide advantages in terms of low production cost, lower capital investment in infrastructure, and suitable post-translational modifications. The major limitation of plants as an expression host is the low level of transgene expression. To increase the expression of heterologous proteins in plants, a number of approaches have been used. One of the approaches is to increase the transgene expression by using tissue-specific promoter(s) which can concentrate the protein of interest in targeted tissues and, thus, prove advantageous in downstream purification. In the present report, a protocol for expression of heterologous protein erythropoietin in potato tuber using patatin, the tuber-tissue-specific promoter, was standardized. Expression vectors for production of the erythropoietin gene under tissue-specific promoter were successfully constructed. For production of a transgenic plant, tissue culture techniques for regeneration of the whole plant from single explants were standardized. Polymerase chain reaction (PCR) analysis was performed to confirm the stable integration of the erythropoietin gene in the potato plant by using sequence-specific primers. How to cite this article: Desai PN, Padh H (2012) Expression of erythropoietin in Indian tetraploid potato variety [v1; ref status: not approved 2, http://f1000r.es/USGpfK] F1000 Research 1:26 (doi: 10.3410/f1000research.1-26.v1) © Usage Licensed by Creative Commons CC-BY 3.0 Introduction In the past decade, transgenic plant expression systems have emerged as a serious competitive force in the large-scale production of recombinant proteins. The first plant-derived heterologous proteins have already reached the market1,2 and detailed economic evaluations have demonstrated their competitiveness against established market sectors3,4. Several plant-derived recombinant therapeutic proteins which are in the final stage of clinical trials include human blood products, vaccine, antibody and growth hormones5. As with a number of products coming to the market, molecular farming in plants is finally coming of age. There have been technological developments on many levels, including transformation methods, control of gene expression, protein targeting and accumulation, the use of different crops as production platforms6 and modifications to alter the structural and functional properties of the product. One of the most driving factors has been yield improvements, as product yield has a significant impact on economic feasibility. To increase the final yield, a number of approaches can be used. One of them is to use a tissue-specific promoter, which can concentrate the protein of interest into targeted tissue and prove advantageous during downstream purification7. In the present report, a protocol for expression of therapeutic proteins in potato tuber by using patatin, a tuber-specific promoter, was made. Indian tetraploid potato variety, Kufri Bahar was used for the expression of the therapeutic protein, as it is widely grown in Gujarat and other region of India. Potato is a vegetative propagated plant, which minimizes the spread of