Development of humanized sugar chain in silkworm targeting for production of next-generation medical glycoprotein

为了提供从高甘露糖型家蚕合成接近哺乳动物细胞的复杂类型的糖链的能力，我们尝试修饰家蚕的糖链合成途径。采用RNA沉默技术后，Bm 5细胞和家蚕的N-乙酰氨基葡萄糖苷酶活性均比对照降低了60%。表达作为测试分子的IgG，并分析糖链。IgG中的寡甘露糖链占总糖链的70%~ 80%，说明N-乙酰氨基葡萄糖苷酶的沉默作用不足以改变家蚕的糖链合成途径。这些结果表明，N-乙酰氨基葡萄糖转移酶可能需要在家蚕中将甘露糖型修饰为复合型。

In order to provide an ability to synthesize sugar chains close to the complex type of mammalian cells from high mannose type of silkworm, we tried to modify the sugar chain synthetic pathway of silkworm. The activity of targeting N-acetylglucosaminidase in both Bm 5 cell and silkworm was decreased to 60% compared to control by adopting RNA silencing technology. As a test molecule IgG was expressed, and analyzed sugar chains. The paucimannose sugar chain of IgG accounted for 70% to 80% of the total, which suggests that silencing effect of N-acetylglucosaminidase was not enough to modify sugar chain synthetic pathway of silkworm. These results indicate that N-acetylglucosaminiltransferase may need to modify mannose type to complex type in silkworm.