Li X, Franceschi V R, Okita T W
Department of Genetics and Cell Biology, Washington State University, Pullman 99164-6340.
Cell. 1993 Mar 26;72(6):869-79. doi: 10.1016/0092-8674(93)90576-c.
Developing rice endosperm cells display two distinct rough endoplasmic reticula (ER), cisternal ER (C-ER) and protein body ER (PB-ER), the latter delimiting the prolamine protein bodies. These ER membranes are utilized for the simultaneous synthesis of glutelin and prolamine storage proteins, which are subsequently routed into separate protein bodies. We demonstrate by blot hybridization, and by visualization of the spatial distributions and densities of these transcripts in endosperm cells via high resolution in situ hybridization analysis, that prolamine transcripts are associated primarily with the PB-ER, while glutelin mRNAs are enriched on the C-ER. The results suggest that the initial targeting process of these storage proteins into distinct protein bodies is the segregation of their transcripts on the ER membranes.
发育中的水稻胚乳细胞呈现出两种不同的粗糙内质网（ER），即扁平囊内质网（C-ER）和蛋白体内质网（PB-ER），后者界定了醇溶蛋白体。这些内质网膜用于同时合成谷蛋白和醇溶蛋白储存蛋白，随后这些蛋白被分别输送到不同的蛋白体中。我们通过印迹杂交以及通过高分辨率原位杂交分析观察胚乳细胞中这些转录本的空间分布和密度，证明醇溶蛋白转录本主要与PB-ER相关，而谷蛋白mRNA在C-ER上富集。结果表明，这些储存蛋白最初靶向进入不同蛋白体的过程是它们的转录本在内质网膜上的分离。
