Expression of Human Soluble Trail Protein in Transgenic Tobacco Nc89

Plant bioreactors have been considered as an efficient system for biopharmaceutical production. It offers many advantages, such as low cost of production, eukaryotic expression way and absence of human pathogens. In this study, we tried to express the soluble extracellular domain of human tumor necrosis factor related apoptosis-inducing ligand (sTRAIL) in transgenic plants of NC89, a tobacco variety that was planted widely. Using the chloroplast-targeted expression vector pGTPsT, which was constructed previously, we transformed NC89 tobacco leaf explants with the mediation of Agrobacterium tumefaciens LBA4404. We used kanamycin resistance to select transformants and PCR analysis to confirm the presence of sTRAIL gene. Then, we performed RT-PCR analysis to detect the transcription of sTRAIL gene and Western blot to analyze sTRAIL protein accumulation in the leaves of the transformed tobacco plants. The results showed that sTRAIL was successfully inserted into NC89 genome of 8 independent transgenic lines and was expressed in all tested lines. However, no significant protein accumulation was detected at present analysis conditions. This suggests that the accumulation of sTRAIL in transgenic plants of NC89 is much lower than that in transgenic Petit Havana, another variety, which we have investigated previously. NC89, therefore, may not be a suitable plant variety used as plant bioreactor for foreign protein expression and accumulation. A strong protein degradation system may exist in the chloroplast of this variety. However, this point should by experimently tested in the future study.