LOCALIZED RNAS--DORSAL AND GERM CELL DETERMINANTS

定位的母体mRNAs可以为区域 形成早期胚胎模式的信息。我们已经确定了 植物皮层作为定位的母体RNA所在的区域 集中起来，已经隔离了其中的七个。其中四个似乎是 涉及两条关键路径，一条指定背轴，另一条指定 其他建立生殖细胞谱系的人。XCAT-2、xCAT-3和B6是 种质的组成部分，并由 原始生殖细胞(PGCs)。BEI是一种可能的转录因子 与可以诱导次级背轴的短臂(T-基因)有关。 在该方案中，实验被概述为：(1)确定空间 以及XCAT的RNA定位和蛋白质合成的时间模式。 2、xCAT-3和B6与PGC的发展、迁移和 分化；(2)确定XCAT-2、XCAT-3和B6的功能为 生殖细胞规格中种质成分；(3)鉴定 其他基因在生殖细胞种质中的表达；(4)决定 被的表达和合成的时空模式及其关系 与其核进入、皮质旋转和背侧活动有关； (5)确定BEAT是否激活早期转录。 参与非洲爪哇中胚层图案化的反应基因。 一般的策略将是在 整装XCAT-2、XCAT-3、B6和BEY的RNA和蛋白质水平 原位杂交、免疫组织学分析和核糖核酸酶保护。 功能丧失、过度表达和异位表达表型 将对这些基因进行研究，以确定它们在 发展。 通过研究定位的RNA，我们希望了解它们是如何引导轴向的 在早期胚胎中形成图案，并建立未来的生殖系。多么 多能性在生殖系中保持，因为它分化出残体 未知的，对人体器官再生和研究很重要 癌症。我们的研究也应该提供关于背轴是如何 (神经管、后脑、体节的正确排列)在 脊椎动物。这样的信息将使我们能够了解哪些基因 可能与影响这一轴的先天缺陷有关。

Localized maternal mRNAs can provide the molecular basis for regional information that patterns the early embryo. We have identified the vegetal cortex as a region in which localized maternal RNAs are concentrated and have isolated seven of them. Four of these appear to be involved in two critical pathways one specifying the dorsal axis and the other establishing the germ cell lineage. Xcat-2, Xcat-3 and B6 are components of the germ plasm and are inherited exclusively by the primordial germ cells (PGCs). Bei is a putative transcription factor related to brachyury (T-gene) that can induce a secondary dorsal axis. In this proposal experiments are outlined to: (1) determine the spatial and temporal pattern of RNA localization and protein synthesis for Xcat- 2, Xcat-3 and B6 in relation to PGC development, migration, and differentiation; (2) determine the function of Xcat-2, Xcat-3 and B6 as components of the germ plasm in germ cell specification; (3) identify other genes expressed in the germ plasm of PGCs; (4) determine the spatial and temporal pattern of bei expression and synthesis in relation to its nuclear entry, cortical rotation, and dorsalizing activity; and (5) establish whether bei activates the transcription of the early response genes involved in patterning the mesoderm in Xenopus. The general strategy will be to establish the expression pattern at the RNA and protein level for Xcat-2, Xcat-3, B6 and bei using whole mount in situ hybridization, immunohistological analysis, and RNase protection. Loss of function, overexpression, and ectopic expression phenotypes of these genes will be studied to determine their possible functions during development. By studying localized RNAs we hope to understand how they direct axial patterning in the early embryo and establish the future germ line. How pluripotency is maintained in the germline as it differentiates remains unknown and is important to studies of human organ regeneration and cancer. Our studies should also provide insights into how the dorsal axis (neural tube, hind brain, correct alignment of somites) is determined in vertebrates. Such information will allow an understanding of what genes may be involved in birth defects which affect this axis.