Cell Interactions and Cell Fate Specification

这项研究的目的是阐明后生动物胚胎形成模式的基本机制。 Ettensohn博士试图定义特定卵裂球相互作用在建立胚胎基因表达领域中的确切作用，并阐明这种相互作用的分子途径。 这项工作还解决了有条件的命运规范的问题-分配细胞命运的非自主的，上下文相关的机制-和胚胎调控的历史问题。 本研究以海胆为模型系统，利用一套功能强大的细胞和分子生物学工具进行研究。研究的三个具体目标是：1）研究ets家族转录调节因子中的一员Lv-ets在正常发育过程中以及通过胚胎操作使新的细胞谱系表达成骨命运时，在成骨特化中的作用。 他将探索Wnt/β-catenin信号传导的可能性，它已被证明可以调节骨骼生成的规范，通过改变Lv-ets蛋白的表达和/或定位。 2)已知来自植物区域的信号调节覆盖细胞的命运。 他将通过使用新的细胞消融方法，新的细胞重组实验和新的分子标记物来完善我们对这种信号在模式化中的作用的理解。 他将直接测试植物到动物的信号级联模式早期海胆胚胎的模型。 3)Wnt/β-连环蛋白信号通路在许多生物体的模式中发挥着重要作用。 最近的研究提供了强有力的证据表明，这一途径的组成部分参与分配细胞的命运沿着动物-植物轴的海胆胚胎。 他将使用GSK 3，C-cadherin和突变（激活）β-catenin mRNA的过表达，结合胚胎操作和分子标记来阐明该途径在模式中的作用。Ettensohn博士将使用胚胎解离研究来测试海胆（可能还有其他后生动物胚胎）中β-连环蛋白核定位的发育编程模式是否依赖于细胞-细胞信号传导，或者受细胞自主机制的调节。 最后，他将研究抑制Wnt/β-连环蛋白通路阻断骨骼发育特化的机制。

The goal of the proposed research is to elucidate fundamental mechanisms involved in patterning metazoan embryos. Dr. Ettensohn seeks to define the precise roles of specific blastomere interactions in establishing territories of gene expression in the embryo and to elucidate molecular pathways that underlie such interactions. This work also addresses the problem of conditional fate specification- the allocation of cell fates by non-autonomous, context-dependent mechanisms- and the historical problem of embryonic regulation. The model system to be used is the sea urchin, which can be studied using a powerful set of cell and molecular biological tools.Three specific objectives are to be pursued: 1) He will examine the role of Lv-ets, a member of the ets family of transcriptional regulators, in skeletogenic specification during normal development and when novel cell lineages are caused to express a skeletogenic fate by embryo manipulation. He will explore the possibility that Wnt/beta-catenin signaling, which has been shown to regulate skeletogenic specification, does so by altering Lv-ets protein expression and/or localization. 2) Signals from the vegetal region are known to regulate the fates of overlying cells. He will refine our understanding of the role of such signals in patterning through the use of new cell ablation methods, novel cell recombination experiments, and new molecular markers. He will directly test the model that a vegetal-to-animal cascade of signals patterns the early sea urchin embryo. 3) The Wnt/beta-catenin signaling pathway plays an important role in patterning in many organisms. Recent studies have provided strong evidence that components of this pathway are involved in the allocation of cell fates along the animal-vegetal axis of the sea urchin embryo. He will use overexpression of GSK3, C-cadherin, and mutant (activated) beta-catenin mRNAs in combination with embryo manipulation and molecular markers to clarify the role of this pathway in patterning. Dr. Ettensohn will use embryo dissociation studies to test the central question of whether the developmentally programmed pattern of nuclear localization of beta-catenin in the sea urchin (and possibly other metazoan embryos) is dependent on cell-cell signaling, or is regulated by a cell-autonomous mechanism. Finally, he will examine the mechanism by which suppression of the Wnt/beta-catenin pathway blocks skeletogenic specification.