REGULATION OF BETA-CATENIN NUCLEARIZATION

β-连环蛋白核化的调控

• 批准号: 6573267
• 负责人: CHARLES A. ETTENSOHN
• 金额: $ 24.56万
• 依托单位: CARNEGIE-MELLON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6573267
• 关键词: affinity chromatography; cadherins; cell cell interaction; cell nucleus; cellular polarity; confocal scanning microscopy; early embryonic stage; enzyme activity; fluorescence microscopy; fluorescence resonance energy transfer; glycoprotein biosynthesis; green fluorescent proteins; immunoprecipitation; microinjections; protein degradation; protein transport; sea urchins; serine threonine protein kinase

DESCRIPTION (provided by applicant): The accumulation of beta-catenin in the nuclei of specific blastomeres is a critical early step in animal development. In all deuterostomes (echinoderms and chordates/vertebrates) that have been studied, accumulation of beta-catenin in the nuclei of specific blastomeres along the axis of the cleavage stage embryo is one of the first indications of embryonic polarity. This differential "nuclearization" of beta-catenin is essential for proper germ layer formation and the establishment of inductive centers. The sea urchin embryo is a powerful model system for studying beta-catenin nuclearization. The embryo develops externally and is optically transparent, facilitating the application of a wide variety of light optical technologies. The system is unique in that specific cell types can be isolated from early embryos in large quantities. Most of the molecules of the beta-catenin pathway have been cloned from sea urchin and a large number of molecular biological tools are available. Gene expression can be manipulated by expression of dominant negative constructs and by microinjection of "morpholino" antisense oligonucleotides. The proposed work will identify the mechanisms that underlie beta-catenin nuclearization in early embryos. There are two major aims: 1) Using GFP-tagged proteins and time-lapse, 3-D confocal microscopy, the dynamics and turnover of key regulators of beta-catenin degradation will be studied in vivo. We will measure the half-life of beta-catenin in specific blastomeres of the early embryo, which will provide essential information concerning the cellular and molecular mechanisms of differential nuclearization. Through blastomere isolation experiments, we will test the role of cell-cell interactions in regulating beta-catenin nuclearization. 2) We will test three major models of GSK3 regulation along the embryo axis. In addition, using dominant negative constructs and morpholinos, we will examine the developmental function of two regulators of GSK3 activity, disheveled and Akt/PKB.

描述（由申请人提供）：β-连环蛋白在特定卵裂球细胞核中的积累是动物发育的关键早期步骤。在所有已研究的后口动物（棘皮动物和脊索动物/脊椎动物）中，沿着卵裂期胚胎轴的特定卵裂球细胞核中β-连环蛋白的积累是胚胎极性的首要迹象之一。 β-连环蛋白的这种差异“核化”对于适当的胚层形成和诱导中心的建立至关重要。海胆胚胎是研究β-连环蛋白核化的强大模型系统。胚胎在外部发育且光学透明，有利于各种光光学技术的应用。该系统的独特之处在于可以从早期胚胎中大量分离特定的细胞类型。 β-连环蛋白途径的大部分分子已从海胆中克隆出来，并且有大量的分子生物学工具可供使用。可以通过显性失活构建体的表达和通过显微注射“吗啉代”反义寡核苷酸来操纵基因表达。拟议的工作将确定早期胚胎中β-连环蛋白核化的机制。主要目标有两个：1) 使用 GFP 标记蛋白和延时 3-D 共聚焦显微镜，在体内研究 β-连环蛋白降解的关键调节因子的动态和周转。我们将测量早期胚胎特定卵裂球中β-连环蛋白的半衰期，这将提供有关差异核化的细胞和分子机制的重要信息。通过卵裂球分离实验，我们将测试细胞间相互作用在调节β-连环蛋白核化中的作用。 2）我们将测试GSK3沿胚胎轴调控的三种主要模型。此外，使用显性失活构建体和吗啉代，我们将检查 GSK3 活性的两个调节因子 disheveled 和 Akt/PKB 的发育功能。