Collaborative Project: Role of Localized Maternal RNA's in Embryonic Patterning in Xenopus

两栖动物的卵子在受精前是轴对称的：它的 内容是沿沿着极化的， 轴线胚胎发育的最早阶段 两侧对称的身体平面，背腹轴 规格，发生在受精后，但发病前 合子基因的表达。因此，所有必要的组件 因为这种模式化事件已经在受精时出现， 并在背侧过程中变得不对称地定位或改变- 腹轴规格。该项目旨在确定 这些组件决定了它们的定位机制， 并评估它们在青蛙背腹图案中的作用 非洲爪蟾两个cDNA文库富集了背侧或背侧的cDNA， 最近构建了胚胎中的腹侧转录物。几 代表区域富集的母体转录物的克隆具有 被孤立。地高辛标记的反义RNA探针， 目前用于原位杂交分析， 相应的RNA的定位的细节， 卵子发生和早期发育。空间、时间和 特定RNA表达的定量变化将是 与胚胎的最终形态相比， 离心、UV照射和过表达注射的 母体mRNA。这些分析将用于确定 转录本参与了早期模式的启动 事件通过提供关于 一些母体转录本相对于 特定合子转录物的调节，这些实验 将有助于我们更好地理解 卵子组织和胚胎模式。

The amphibian egg is axially symmetric before fertilization: its contents are polarized along one dimension, the animal-vegetal axis. The earliest step in the establishment of the embryo's bilaterally symmetric body plan, dorsal-ventral axis specification, occurs after fertilization, but before the onset of zygotic gene expression. Thus, all the components necessary for this patterning event are already present at fertilization, and become asymmetrically localized or modified during dorsal- ventral axis specification. This project proposes to identify such components, determine the mechanisms of their localization, and assess their roles in dorsal-ventral patterning in the frog Xenopus laevis. Two cDNA libraries enriched for either dorsal or ventral transcripts in embryos were recently constructed. Several clones representing regionally enriched maternal transcripts have been isolated. Digoxigenin labelled antisense RNA probes are presently being used for in situ hybridization analysis to learn the details of localization of the corresponding RNAs during oogenesis and early development. The spatial, temporal, and quantitative changes in expressions of specific RNAs will be compared with the final morphology of embryos subjected to centrifugation, UV irradiation, and over expression of injected maternal mRNAs. These analyses will be used to ascertain which transcripts are involved in the initiation of early pattern events. By providing new information on the relationships between the spatial localization of some maternal transcripts relative to the regulation of specific zygotic transcripts, these experiments will lead to a better understanding of the relationship between egg organization and embryonic patterning.