水稻GPH3突变体胚乳贮藏蛋白质蓄积状态的解析

摘要

在野生型水稻胚乳细胞中,醇溶蛋白与谷蛋白在内质网(ER)中被合成后、最终分别蓄积成内质网衍生型蛋白体(PBⅠ)与液泡型蛋白体(PBⅡ).已有报道显示,导致57 ku谷蛋白前体高量蓄积、成熟谷蛋白显著减少的57H变异被表明是调控贮藏蛋白质翻译后蓄积的基因突变.山西大学生命科学学院种质资源遗传实验室已报道了3个成熟谷蛋白未减少的新型57H突变体(GPH系列).为了阐明新型57H突变对贮藏蛋白生成的影响,研究解析了GPH3胚乳贮藏蛋白质的亚细胞蓄积状态.基于电子染色的电显观察显示了GPH3突变体胚乳细胞中内质网衍生的复合蛋白体结构的存在,免疫标记的电显观察指出,GPH3中复合蛋白体结构由醇溶蛋白颗粒及其表面包被的谷蛋白前体颗粒组成.这些结果说明,GPH3突变可能与贮藏蛋白的合成有关,并影响其蓄积状态.%Prolamins and glutelins,the main storage proteins in endosperm of the wild type rice,are synthesized in the ER,and finally deposites into the ER-derived protein body (PB Ⅰ) and vacuolar protein body (PB Ⅱ),respectively.It has been reported that the 57H mutations caused the high deposition of 57 ku glutenin precursors and the decreased deposition of the mature glutelins.We have reported the three novel 57H mutants (GPH series) in which the mature glutelins are not decreased.In this study,we investigated analysis of the sub-cellular deposited state of storage proteins in the GPH3 endosperm,to understand effect of the GPH3 mutation on generation of storage proteins in rice endosperm.Electron-microscopic observation,based on electron staining,showed the existence of complex structures of protein granules derived from the ER in the GPH3 endosperm cell.Microscopic observation,based on immuno-gold labeling,showed that the complex protein granuled structure in the GPH3 was composed of prolamin granule and glutelin precursor granules on its surface.These results indicated that the GPH3 mutation is likely to concern on synthesis of storage proteins and affect their deposited state in rice endosperm.