High level accumulation of soybean glycinin in vacuole-derived protein bodies in the endosperm tissue of transgenic tobacco seed
High level accumulation of soybean glycinin in vacuole-derived protein bodies in the endosperm tissue of transgenic tobacco seed
复制标题
转基因烟草种子胚乳组织液泡来源蛋白体中大豆甘氨酸的高水平积累
DOI：
10.1016/0168-9452(95)04215-g
复制
发表时间：
1995
期刊：
影响因子：
5.2
通讯作者：
S. Utsumi
中科院分区：
文献类型：
--
作者：
F. Takaiwa;T. Katsube;Sayuri Kitagawa;Takahiko Hisago;M. Kito;S. Utsumi
大豆球蛋白基因在成熟大豆种子的子叶和胚胎中特异表达，胚乳组织由此退化。为了检测大豆球蛋白能否在胚乳组织中稳定积累，将大豆球蛋白基因转录融合到水稻贮藏蛋白谷蛋白基因的胚乳特异启动子上，然后通过农杆菌介导法导入烟草基因组。因此，大豆球蛋白基因在转基因烟草种子中以种子和发育特异的方式表达。大豆球蛋白定位于胚乳组织中液泡衍生的蛋白体，并在许多转基因植物的基质区域高度积累(占种子总蛋白的1-4%)。人工合成的球蛋白被加工成成熟的形式，并以类似于大豆种子中的球蛋白的方式组装成六聚体。然而，值得注意的是，大约一半的合成球蛋白对有限的降解很敏感，而且组装成六聚体是不够的。修饰的球蛋白在酸性和碱性多肽的C-末端对应的可变区插入了4个连续的蛋氨酸残基，也发现了与正常球蛋白相似的积累。正常和修饰后的大豆球蛋白在表达水平、对蛋白质小体的加工和靶向性、积累水平等方面没有明显差异。
Soybean glycinin genes are expressed specifically in the cotyledon and embryo of maturing soybean seed, from which the endosperm tissue is degenerated. To examine whether glycinin could be stably accumulated in endosperm tissue, the glycinin cDNA was transcriptionally fused to an endosperm-specific promoter of the rice storage protein glutelin gene and then introduced into tobacco genome via Agrobacterium-mediated transformation. Consequently the glycinin gene was expressed in a seed- and developmentally-specific manner in transgenic tobacco seeds. Glycinins were targeted to vacuole-derived protein bodies in the endosperm tissue and highly accumulated in the matrix region of many transgenic plants (1–4% of total seed proteins). Synthesized glycinin was processed into mature form, and assembled into a hexamer in a similar manner as the glycinin in soybean seed. However, it was noteworthy that about half of the synthesized glycinin was susceptible to limited degradation and that assembly into a hexamer was insufficient. Modified glycinins, in which 4 contiguous methionine residues were inserted at the variable regions corresponding to the C-terminal regions of the acidic and basic polypeptides, were also found to be accumulated similarly as in the normal glycinin. There was no apparent difference in the expression level, processing and targeting to protein bodies, or accumulation level between normal and modified glycinins.