Mori Takashi, Maruyama Nobuyuki, Nishizawa Keito, Higasa Takahiko, Yagasaki Kazuhiro, Ishimoto Masao, Utsumi Shigeru
Laboratory of Food Quality Design and Development, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
Plant J. 2004 Oct;40(2):238-49. doi: 10.1111/j.1365-313X.2004.02204.x.
Glycinin (11S) and beta-conglycinin (7S) are major storage proteins in soybean (Glycine max L.) seeds and accumulate in the protein storage vacuole (PSV). These proteins are synthesized in the endoplasmic reticulum (ER) and transported to the PSV by vesicles. Electron microscopic analysis of developing soybean cotyledons of the wild type and mutants with storage protein composition different from that of the wild type showed that there are two transport pathways: one is via the Golgi and the other bypasses it. Golgi-derived vesicles were observed in all lines used in this study and formed smooth dense bodies with a diameter of 0.5 to several micrometers. ER-derived protein bodies (PBs) with a diameter of 0.3-0.5 microm were observed at high frequency in the mutants containing higher amount of 11S group I subunit than the wild type, whereas they were hardly observed in the mutants lacking 11S group I subunit. These indicate that pro11S group I may affect the formation of PBs. Thus, the composition of newly synthesized proteins in the ER is important in the selection of the transport pathways.
大豆球蛋白(11S)和β-伴大豆球蛋白(7S)是大豆(Glycine max L.)种子中的主要贮藏蛋白,它们积累在蛋白贮藏液泡(PSV)中。这些蛋白质在内质网(ER)中合成,并通过囊泡运输到PSV。对野生型和贮藏蛋白组成与野生型不同的突变体的发育中大豆子叶进行电子显微镜分析表明,存在两条运输途径:一条是通过高尔基体,另一条则绕过高尔基体。在本研究使用的所有品系中均观察到来自高尔基体的囊泡,它们形成了直径为0.5至数微米的光滑致密体。在含有比野生型更多的11S I组亚基的突变体中,高频观察到直径为0.3 - 0.5微米的源自内质网的蛋白体(PBs),而在缺乏11S I组亚基的突变体中几乎未观察到。这些表明pro11S I组可能影响PBs的形成。因此,内质网中新合成蛋白质的组成在运输途径的选择中很重要。