Expression of a Fusion Protein Consisting of Cholera Toxin B Subunit and an Anti-Diabetic Peptide (p277) from Human Heat Shock Protein in Transgenic Tobacco Plants

A DNA construct encoding cholera toxin B subunit (CTB) and an anti-diabetic peptide from human heat shock protein 60 (hsp60) as a fusion protein was produced and transferred into low-nicotine tobacco through Agrobacterium-mediated transformation. Integration of the fusion gene into the plant genome was confirmed by PCR. The transcriptional expression of the fusion gene was demonstrated by RTPCR. Western blot analysis further verified the synthesis and assembly of the fusion protein into pentamers in transgenic tobacco. GM1ELISA showed that the plant-derived fusion protein retained GM1-ganglioside receptor binding specificity. The fusion protein accounted approximately for 0.1% of the total leaf protein. The production of transgenic plants expressing CTB-p277 offers an opportunity to test plant tissues for oral peptide antigen therapy against autoimmune diabetes by inducing oral tolerance. _____________________________________________________________________________________________________________