Synthesis of a cholera toxin B subunit-rotavirus NSP4 fusion protein in potato

To increase the efficacy of the small amounts of therapeutic protein generally synthesized in transformed plants, we investigated the feasibility of producing a fusion protein in potato capable of targeting a therapeutic protein to a specific organ in the body. An enterocyte-targeted rotavirus fusion gene was constructed by linking the gene encoding the cholera toxin B subunit (CTB) to a DNA fragment encoding an epitope of the rotavirus enterotoxin protein (NSP4). Solanum tuberosum plants carrying a plant expression vector harboring the fusion gene were generated by Agrobacterium tumefaciens-mediated in vivo transformation methods. Immunoblot analysis of transformed tubers indicated the presence of the CTB-NSP4 fusion protein oligomers that retained enterocyte receptor G_MI ganglioside binding affinity. The CTB-NSP4 fusion protein multimers were synthesized in the range of 0.01-0.1% of the total soluble tuber protein.