Hennegan Kevin, Yang Daichang, Nguyen Diane, Wu Liying, Goding Jeff, Huang Jianmin, Guo Fengli, Huang Ning, Watkins Simon C
Ventria Bioscience, 4110 North Freeway, Sacramento, CA 95834, USA.
Transgenic Res. 2005 Oct;14(5):583-92. doi: 10.1007/s11248-004-6702-y.
Heterologous protein expression levels in transgenic plants are of critical importance in the production of plant-made pharmaceuticals (PMPs). We studied a puroindoline b promoter and signal peptide (Tapur) driving human lysozyme expression in rice endosperm. The results demonstrated that human lysozyme expressed under the control of the Tapur cassette is seed-specific, readily extractable, active, and properly processed. Immuno-electron microscopy indicated that lysozyme expressed from this cassette is localized in protein bodies I and II in rice endosperm cells, demonstrating that this non-storage promoter and signal peptide can be used for targeting human lysozyme to rice protein bodies. We successfully employed a strategy to improve the expression of human lysozyme in transgenic rice grain by combining the Tapur cassette with our well established Gt1 expression system. The results demonstrated that when the two expression cassettes were combined, the expression level of human lysozyme increased from 5.24 +/- 0.34 mg(-1) g flour for the best single cassette line to 9.24 +/- 0.06 mg(-1) g flour in the best double cassette line, indicating an additive effect on expression of human lysozyme in rice grain.
转基因植物中异源蛋白的表达水平对于植物源药物（PMPs）的生产至关重要。我们研究了一种驱动人溶菌酶在水稻胚乳中表达的麦醇溶蛋白-吲哚啉b启动子和信号肽（Tapur）。结果表明，在Tapur盒控制下表达的人溶菌酶具有种子特异性、易于提取、有活性且加工正确。免疫电子显微镜显示，从该盒表达的溶菌酶定位于水稻胚乳细胞中的蛋白体I和II中，表明这种非储存型启动子和信号肽可用于将人溶菌酶靶向水稻蛋白体。我们通过将Tapur盒与我们成熟的Gt1表达系统相结合，成功采用了一种策略来提高转基因水稻籽粒中人溶菌酶的表达。结果表明，当两个表达盒组合时，人溶菌酶的表达水平从最佳单盒系的5.24±0.34 mg（-1）g面粉增加到最佳双盒系的9.24±0.06 mg（-1）g面粉，表明对水稻籽粒中人溶菌酶的表达有累加效应。
