Matsuno A, Utsunomiya H, Ohsugi Y, Takekoshi S, Sanno N, Osamura R Y, Nagao K, Tamura A, Nagashima T
Department of Neurosurgery, Teikyo University Ichihara Hospital, Chiba, Japan.
Histochem J. 1996 Oct;28(10):703-7. doi: 10.1007/BF02409007.
The present electron microscopical study is concerned with the simultaneous visualization of messenger ribonucleic acid (mRNA) and its encoded protein in the same specimen. Pre-embedding electron microscopical in situ hybridization (EM-ISH) on rat pituitary gland tissue localized growth hormone mRNA in the polysomes of the rough endoplasmic reticulum, and subsequent postembedding immunolabelling using protein A-colloidal gold particles identified growth hormone mainly in the secretory granules. We believe that our report provides the first simultaneous ultrastructural identification of mRNA and its encoded protein using combined pre-embedding EM-ISH and immunohistochemistry. In this method, the signals for mRNA were localized specifically as highly electron dense products on the polysomes of the endoplasmic reticulum, and those for its encoded protein were recognized as gold particles both in the cisternae of the reticulum and in the secretory granules. Our ultrastructural double labelling method for mRNA and protein may provide a tool to find important clues for elucidating the intracellular correlation of mRNA translation and secretion of translated protein, because of its high resolution, good morphological preservation, and the specific localization of the reaction products.
目前的电子显微镜研究关注的是在同一标本中同时可视化信使核糖核酸（mRNA）及其编码的蛋白质。对大鼠垂体组织进行预包埋电子显微镜原位杂交（EM-ISH），将生长激素mRNA定位在内质网多核糖体中，随后使用蛋白A胶体金颗粒进行包埋后免疫标记，主要在分泌颗粒中鉴定出生长激素。我们认为，我们的报告首次使用预包埋EM-ISH和免疫组织化学相结合的方法对mRNA及其编码蛋白进行了超微结构鉴定。在这种方法中，mRNA的信号作为高度电子致密产物特异性地定位在内质网的多核糖体上，而其编码蛋白的信号则在内质网池和分泌颗粒中被识别为金颗粒。我们用于mRNA和蛋白质的超微结构双重标记方法可能提供一种工具，用于寻找重要线索以阐明mRNA翻译与翻译后蛋白质分泌的细胞内相关性，因为它具有高分辨率、良好的形态保存以及反应产物的特异性定位。
