| Summary: | 碩士 === 國立嘉義大學 === 生物農業科技學系研究所 === 106 === To develop more efficient plant-based protein expression systems, the availability of promoters that provide reliable high-level production of foreign proteins in transgenic plants becomes increasingly important. One strategy is to modify promoters by adding muLtiple copies of enhancers to increase the promoter strength. The rice glutelin genes confer high-level promoter activity and are currently the most commonly used promoters to produce commercially valuable proteins in transgenic rice. Our earlier studies showed that a modified -amylase transcriptional enhancer, modified Amy8 SRC/GARC, can increase the promoter activity of two glutelin genes, GluA-2(Gt1) and GluB1, in transgenic rice cells and seeds. Our previous resuLts also revealed that the activity of GluB1 promoter is higher than the Gt1 promoter, and the modified Amy8 SRC/GARC enhancer significantly enhances Gt1 and GluB1 promoter activities in transgenic rice cells and developing seeds. In the present study, transgenic approach and Agrobacteria-mediated co-transformation were employed to analyze the activity of glutelin promoter. The OsMYBGA gene, which encodes a gibberellin response element (GARE)-binding transcription factor, was employed to promote the transcription of the mGluB1 promoter. We found that OsMYBGA drastically stimuLates promoter activity of mGluB1 in both rice suspension cells and developing seeds. The modified GluB1 promoter was used to produce the recombinant human acidic fibroblast growth factor (haFGF) in rice. Our resuLt shows that the bioactive recombinant haFGF is stably produced in transformed rice cells with a yield are up to 0.4-0.5% of total soluble proteins. Thus, our studies demonstrate that modified Amy8 SRC/GARC serves as a transcriptional enhancer and the mGluB1 promoter can be applied to in establish an efficient expression system for high-level production of foreign proteins in transgenic rice.
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