Expression of human soluble tumor necrosis factor (TNF)-related apoptosis-inducing ligand in transplastomic tobacco
The soluble extracellular domain of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (sTRAIL) can, as the whole length TRAIL protein, bind with its receptors and specifically induce the apoptosis of cancer cells; therefore, it has been developed as a potential therapeutic agent for various cancer treatments. As it has become an attractive technology for foreign protein production, especially for production of biopharmaceuticals, chloroplast engineering was applied in this study to express human sTRAIL protein in tobacco. Two transplastomic lines were obtained. Southern blot showed that sTRAIL gene was inserted into the right site of the tobacco chloroplast genome. RT-PCR results also confirmed that the foreign gene is transcribed in both lines. However, western blot showed that only one line accumulated sTRAIL protein stably, while the other line lost the ability to accumulate this protein after several rounds of subcultures. The possible reason for this unexpected phenomenon is discussed.
Key words: Chloroplast transformation, sTRAIL, pharmaceutical protein, expression, tobacco chloroplast.