Elinson R P, King M L, Forristall C
Department of Zoology, University of Toronto, Ontario, Canada.
Dev Biol. 1993 Dec;160(2):554-62. doi: 10.1006/dbio.1993.1329.
The process of converting an egg to a multicellular organism often begins with a polarization of information within the oocyte. The cytoskeleton plays an important role in maintaining such asymmetries. Here we describe the isolation and characterization of cortices, rich in cytoskeletal elements, from the animal and vegetal poles of stage VI Xenopus oocytes. Ultrastructural and immunocytochemical analyses revealed that the 10-microns-thick isolates included a cytokeratin network, mitochondria, and other elements, found in the oocyte cortex. Furthermore, three vegetally localized mRNAs, Vg1, Xcat-2, and Xcat-3, were all found to be specifically retained within the isolated vegetal cortices, in sharp contrast to histone RNA. Our findings support the view that the vegetal cortex represents a unique cytoskeletal domain in which a rare class of maternal mRNAs becomes localized.
将一个卵细胞转变为多细胞生物体的过程通常始于卵母细胞内信息的极化。细胞骨架在维持这种不对称性方面发挥着重要作用。在这里，我们描述了从第六阶段非洲爪蟾卵母细胞的动物极和植物极分离并鉴定富含细胞骨架成分的皮质。超微结构和免疫细胞化学分析表明，这些10微米厚的分离物包含细胞角蛋白网络、线粒体和卵母细胞皮质中发现的其他成分。此外，三种植物定位的mRNA，即Vg1、Xcat - 2和Xcat - 3，均被发现特异性保留在分离出的植物皮质内，这与组蛋白RNA形成鲜明对比。我们的研究结果支持这样一种观点，即植物皮质代表了一个独特的细胞骨架区域，一类罕见的母源mRNA在其中定位。
