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分解(UMP)在细胞背腹模式形成过程中决定细胞命运的作用。26S蛋白小体的UMP已被证明在调节细胞活动中起关键作用。虽然UMP广泛参与胚胎发育早期的细胞命运决定，但目前对UMP在背腹模式中的确切作用和调控知之甚少，背腹模式是胚层发生和组织和器官个体发育的基础。以前的研究表明，来自背侧信号中心的β-catenin和来自腹侧信号中心的Xom都受UMP控制。众所周知，在胚胎发育的早期，腹侧(XOM)信号会拮抗背侧(连环蛋白)信号；然而，UMP在背侧信号中的内在功能尚不清楚。本申请的目的是确定UMP在平衡背侧和腹侧信号方面的功能。这项研究源于首席研究员的初步研究，这使得他能够提出这样的假设，即XOM通过GSK介导的连环蛋白的蛋白分解来拮抗背部信号。使用生物化学和遗传学相结合的方法和非洲爪哇模型，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GSK3激酶和Ser33/37磷酸化的参与，来确定XOM在体外诱导连环蛋白降解的机制。此外，他们还将确定诱导连环蛋白蛋白分解所需的XOM的关键结构域。目的2通过检测XOM和GSK3在早期胚胎发育过程中对连环蛋白的时空表达模式的影响，确定XOM在体内对连环蛋白UMP的影响。这项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的功能和未来先天性畸形和肿瘤疾病的治疗铺平道路。 项目简介：控制背侧-腹侧轴形成的分子机制是早期胚胎发生的根本挑战。拟议的研究将集中在泛素介导的蛋白分解在背腹图案形成中的作用。这些研究的结果将广泛应用于预防先天性畸形、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.