Yisraeli J K, Melton D A
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138.
Nature. 1988 Dec 8;336(6199):592-5. doi: 10.1038/336592a0.
The animal and vegetal ends of Xenopus oocytes have distinctly different developmental fates. At the molecular level, several maternal mRNAs have been isolated that are localized to either the animal or vegetal hemisphere. One of these mRNAs, Vg1, is distributed homogeneously throughout the cytoplasm of early-stage oocytes and gets localized during oogenesis to a tight shell at the vegetal cortex of middle and late-stage oocytes. We have used an in vitro culture system to demonstrate that exogeneous Vg1 mRNA injected into middle-stage, but not late-stage, oocytes gets localized in a similar fashion to the endogenous message. Furthermore, translation of Vg1 mRNA is not required for the localization of the message itself. These results show that the information necessary to interpret the animal-vegetal polarity in oocytes is present in the naked mRNA transcript.
非洲爪蟾卵母细胞的动物极和植物极具有明显不同的发育命运。在分子水平上，已分离出几种定位于动物半球或植物半球的母源mRNA。其中一种mRNA，即Vg1，在早期卵母细胞的细胞质中均匀分布，并在卵子发生过程中定位于中晚期卵母细胞植物皮质的紧密壳层。我们使用体外培养系统证明，注入中期而非晚期卵母细胞的外源Vg1 mRNA以与内源信息相似的方式定位。此外，Vg1 mRNA的定位并不需要其自身的翻译。这些结果表明，解释卵母细胞中动物-植物极性所需的信息存在于裸露的mRNA转录本中。
