Regulation of beta-catenin proteolysis in dorsal-ventral patterning

描述（由申请人提供）：拟议研究的长期目标是确定泛素介导的蛋白水解（UMP）在背腹图案形成过程中细胞命运决定中的作用。 26 S蛋白体的UMP已被证明在调节细胞活动中起关键作用。 虽然在早期胚胎发生过程中广泛参与细胞命运的决定，但目前对UMP在背腹图案形成中的确切作用和调节知之甚少，背腹图案形成是胚层生成和组织器官个体发生的基础。 先前的研究表明，来自背侧信号中心的<$-catenin和来自腹侧信号中心的Xom都受到UMP的控制。 在早期胚胎发育过程中，腹侧（Xom）信号传导拮抗背侧（<$-连环蛋白）信号传导;然而，UMP在背腹侧信号传导中的内在功能尚不清楚。 本申请的目的是定义UMP在平衡背侧和腹侧信号中的功能。 这项研究来自主要研究者的初步研究，这使他能够提出Xom通过GSK介导的蛋白水解来拮抗背侧信号传导的假设。 使用生物化学和遗传学相结合的方法和非洲爪蟾模型，研究人员建议通过以下两个具体目标进一步验证他们的假设。目的1通过确定GSK 3激酶和Ser 33/37磷酸化的参与，确定Xom诱导的<$-catenin蛋白水解的体外机制。 此外，他们将确定Xom的关键结构域诱导连环蛋白的蛋白水解。 目的2将通过确定Xom和GSK 3在早期胚胎发生过程中对<$-连环蛋白蛋白和mRNA的时空表达模式的影响来确定Xom对<$-连环蛋白体内UMP的影响。 拟议研究的结果将引入背腹不对称形成的新范式，并有望为理解干细胞功能和先天性畸形和肿瘤疾病的未来管理铺平道路。 项目叙述：控制背腹轴形成的分子机制代表了早期胚胎发生的基本挑战。 这些研究将集中在泛素介导的蛋白水解在背腹图案形成中的作用。 这些研究的结果将广泛涉及预防先天性畸形，调节干细胞功能以及管理肿瘤疾病。

DESCRIPTION (Provided by Applicant): The long-term goal of the proposed studies is to define the role of ubiquitin-mediated proteolysis (UMP) in cell fate determination during dorsoventral patterning. UMP by the 26S proteosome has been shown to play critical roles in regulating cellular activities. While broadly implicated in cell fate determination during early embryogenesis, currently little is known about the exact role and regulation of UMP in dorsoventral patterning, which forms the foundation for the generation of germ layers and ontogenesis of tissues and organs. Previous studies have shown that both ¿-catenin from the dorsal signaling center and Xom from the ventral signaling center are controlled by UMP. It is well appreciated that during early embryogenesis, ventral (Xom) signaling antagonizes dorsal (¿-catenin) signaling; nevertheless, the intrinsic function of UMP in dorsoventral signaling is not clear. The goal of this application is to define the function of UMP in balancing dorsal and ventral signals. The research derives from the principal investigator's preliminary studies, which allowed him to formulate the hypothesis that Xom antagonizes dorsal signaling through GSK-mediated proteolysis of ¿-catenin. Using combined biochemical and genetic approaches and a Xenopus model, the investigators propose to further test their hypothesis through the following two specific aims. Aim 1 will determine the mechanisms of Xom-induced proteolysis of ¿-catenin in vitro by defining the involvement of GSK3 kinase and Ser33/37 phosphorylation. In addition they will identify the critical domain of Xom required for inducing proteolysis of ¿-catenin. Aim 2 will define the effects of Xom on UMP of ¿-catenin in vivo by determining the effects of Xom and GSK3 in the temporal and spatial expression pattern of the ¿-catenin protein and mRNA during early embryogenesis. The results of the proposed studies will introduce a new paradigm underlying the formation of dorsal-ventral asymmetry, and are expected to pave the way for understanding stem cell function and future management of congenital malformations and neoplastic diseases. PROJECT NARRATIVE: Molecular mechanisms controlling the formation of dorsal-ventral axis formation represent a fundamental challenge of early embryogenesis. The proposed studies will focus on the role of ubiquitin-mediated proteolysis in dorsoventral patterning formation. The results of these studies will be broadly implicated in preventing congenital malformation, regulating stem cell function, as well as managing neoplastic diseases.