LOCALIZED RNAS--DORSAL AND GERM CELL DETERMINANTS

定位的母体mRNAs可以为区域性表达提供分子基础。 形成早期胚胎的信息。我们已经确定了 植物皮层作为一个区域，其中本地化的母体RNA， 集中并分离出其中七个。其中四个似乎是 涉及两个关键途径，一个指定背轴， 其他的则建立生殖细胞谱系。Xcat-2、Xcat-3和B6是 基因的组成部分，并完全由遗传 原始生殖细胞（PGCs）。 Bei是一个假定的转录因子 与短尾畸形（T基因）相关，可诱导次级背轴。 在这个建议中，实验概述为：（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发育、迁移和 （2）确定Xcat-2、Xcat-3和B6的功能， （3）鉴定植物种质的组成成分 其他基因在PGCs的种质中表达;（4）确定PGCs的 bei表达和合成的时空模式 其核进入、皮质旋转和背侧活动;以及 (5)确定bei是否激活了 参与非洲爪蟾中胚层形成模式的反应基因。 一般的策略是建立表达模式， 使用全载玻片的Xcat-2、Xcat-3、B6和bei的RNA和蛋白质水平 原位杂交、免疫组织学分析和RNA酶保护。 功能丧失、过度表达和异位表达表型 这些基因将被研究，以确定它们可能的功能， 发展 通过研究局部RNA，我们希望了解它们如何引导轴向 在早期胚胎中形成图案并建立未来的生殖系。如何 多能性在生殖系中保持，因为它分化剩余的细胞， 未知，对人体器官再生的研究很重要， 癌我们的研究还应该提供关于背轴如何 （神经管，后脑，体节的正确排列）是在 脊椎动物 这些信息将帮助我们了解 可能与影响该轴的出生缺陷有关。

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.