Plant-produced Asialo-erythropoietin and its Antiapoptotic Functions

在这个项目中，我们利用了植物表达系统的明显优势，这是 缺乏添加唾液酸的能力，无法对植物进行asialo-rHuEPO-a的基因改造 不含唾液酸的特殊糖蛋白。尽管几乎所有的人类糖蛋白都需要唾液酸 对于它们在体内的功能，我们可以发现的一个例外是rHuEPO，它具有 既有造血功能又有组织保护功能。当rHuEPO用作抗细胞凋亡剂时 它的造血活性可通过导致有害的 红细胞团。这种活性可以通过去除唾液酸而被破坏。Asialo-rHuEPO 由rHuEPO的全酶脱氢生成的rHuEPO已被证明保留了 无造血活性的EPO的细胞和组织保护特性。这种类型的EPO 衍生物可作为抗细胞凋亡剂进行开发。但是，没有任何表达式 可直接生产无菌重组人促红细胞生成素的系统。它也不太可能在商业上使用 仅在哺乳动物细胞中产生的可用rHuEPO，用于制造asialo-rHuEPO 因为它的供应量有限。基于现有的知识和技术，它很可能 对植物进行基因改造，以生产不含唾液酸的人类糖蛋白。我们有共同的- 人GalT基因和EPO基因与ER信号肽在烟草中的融合表达， 并尝试廉价生产具有规模化生产潜力的asialo-rHuEPO。 我们预计植物生产的asialo-rHuEPO将具有类似于 酶法生产的阿西洛-rHuEPO。该项目的结果也将提供洞察力 进入植物的糖基化机制和植物的抗凋亡机制- 产生了asialo-rHuEPO。此外，蛋白质纯化方法学将是 建立的糖蛋白分析方法对今后的植物生产具有重要的参考价值。 糖化工程项目。

In this project, we are taking the distinct advantage of plant expression systems, which is the lack of the capacity to add sialic acids, to genetically modify plants for asialo-rhuEPO - a special glycoprotein without sialic acids. Although nearly all human glycoproteins require sialic acid residues for their in vivo functions, the one exception we could find is rhuEPO, which has both hematopoietic and tissue protective functions. When rhuEPO is used as an antiapoptotic agent, its hematopoietic activity can cause bad side effects by leading to harmful increases in red blood cell mass. This activity can be disrupted by removing sialic acids. Asialo-rhuEPO generated by total enzymatic desialylation of rhuEPO has been demonstrated to retain the cell- and tissue-protective properties of EPO without hematopoietic activity. This type of EPO derivative can be explored as the antiapoptotic agent. However, there is no expression system that can produce asialo-rhuEPO directly. It is also unlikely to use commercially available rhuEPO, which is produced only in mammalian cells, to make asialo-rhuEPO because of its limited supply. Based on available knowledge and techniques, it is likely to genetically modify plants to produce human glycoproteins without sialic acids. We have co- expressed human GalT gene and EPO gene fusing with ER-signal peptides in tobacco plants, and try to inexpensively produce asialo-rhuEPO with the potential of large scale production. We expect plant-produced asialo-rhuEPO will have similar cytoprotective function as the enzymatically produced asialo-rhuEPO. The results of this project will also provide insights into the plant glycosylation mechanism and the antiapoptotic mechanism of the plant- produced asialo-rhuEPO. In addition, the protein purification methodologies that will be established and the glycoprotein analysis methods will be very valuable for future plant glycoengineering projects.