Role of the Archipelago gene in Drosophila tracheal morphogenesis

群岛基因在果蝇气管形态发生中的作用

• 批准号: 7571660
• 负责人: Kenneth H Moberg
• 金额: $ 26.78万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7571660
• 关键词: Binding; Biochemical Genetics; Biological; Biological Models; Blood Vessels; Cell Cycle; Cell Proliferation; Cells; Chemotactic Factors; Cyclin E; Data; Defect; Development; Dominant-Negative Mutation; Drosophila genus; Drosophila melanogaster; Duct (organ) structure; Embryo; Epithelial; Eye; F-Box Proteins; Family; Fibroblast Growth Factor; Genes; Genetic Techniques; Genetic screening method; Goals; Histocompatibility Testing; Human; Hypoxia Inducible Factor; Knowledge; Ligase; Mammals; Mitotic; Modeling; Molecular; Morphogenesis; Morphology; Oncogenic; Orthologous Gene; Oxygen; Pathway interactions; Play; Process; Proteins; Recruitment Activity; Research Personnel; Role; Specificity; System; Testing; Tissues; Transgenes; Tube; Ubiquitination; Work; activating transcription factor; base; expectation; fly; gene function; hypoxia inducible factor 1; knock-down; lung development; member; mutant; novel; programs; transcription factor; tumorigenesis; ubiquitin ligase; ubiquitin-protein ligase; unpublished works

DESCRIPTION (provided by applicant): It is our long-term goal to use the fruit fly Drosophila melanogaster as a model system to identify genes that restrict cell proliferation, and to study the functions of these genes in developing tissues. Here we focus on a novel function of the archipelago (ago) gene, which we identified based on its anti-proliferative role in the fly eye, and whose human ortholog Fbw7 was subsequently shown to suppress tumorigenesis in a variety of tissue types. The ago gene encodes an F-box protein (Ago) that targets proteins for proteasomal degradation by binding directly to them, and recruiting them into an SCF E3-ubiquitin ligase for poly- ubiquitination. We have previously identified two Ago targets, the cell cycle regulator Cyclin E, and the proto- oncogenic transcription factor dMyc, both of which are also targeted by Fbw7. However, our lack of knowledge of the full repertoire of ago/Fbw7 targets limits our understanding of the role of the gene in development, and hinders attempts to predict the biological consequences of ago/Fbw7 loss in humans. In the current proposal, we present a substantial body of unpublished work that demonstrates a novel role for the ago ligase in post-mitotic morphogenesis of the fly embryonic tracheal system, a branched network of epithelial tubes similar to the human vasculature which duct oxygen through the developing embryo. We hypothesize that ago acts in this pathway via a novel target: the Trachealess protein (Trh), a member of the Hypoxia Inducible Factor (HIF)-1 alpha family of transcription factors that activates the Fibroblast Growth Factor (FGF) pathway, a known regulator of tracheal development in flies and vascular & lung development in mammals. In Specific Aim 1, we seek to test a hypothesis suggested by our preliminary data that Ago binds Trh in tracheal cells, and targets it for degradation. We have found that ago may act redundantly in this process with the dVHL gene, which encodes a HIF-1 alpha ubiquitin-ligase known to be involved in tracheal development, and in Specific Aim 2, we propose to test genetic and functional interactions between ago and dVHL. We also find that inactivation of ago in mature tissues is able to non-cell autonomously induce ectopic terminal tracheal branching, a process that is normally controlled by oxygen availability. Thus, we hypothesize that ago plays an important role in the homeostatic mechanisms that restrain tracheal branching. Our goal in Specific Aim 3 is to define this role and elucidate its molecular basis.

描述（由申请人提供）：我们的长期目标是使用果蝇果蝇梅拉诺加斯特作为模型系统来识别限制细胞增殖的基因，并研究这些基因在发育组织中的功能。在这里，我们着重于群岛（AGO）基因的新功能，我们根据其在蝇眼中的抗增殖作用识别出来，其人类直系同源物fbw7随后被证明可以抑制多种组织类型中的肿瘤发生。 AGO基因编码一种F-box蛋白（AGO），该蛋白通过直接与它们结合来靶向蛋白质降解蛋白，并将其募集到SCF E3-泛素连接酶中以进行多泛素化。我们以前已经确定了两个AOD靶标，即细胞周期调节剂细胞周期蛋白E和原始性转录因子DMYC，这两者也均由FBW7靶向。但是，我们缺乏对AGO/FBW7的全部曲目的知识限制了我们对基因在发育中的作用的理解，而Hinders试图预测人类AGO/FBW7损失的生物学后果。在当前的提案中，我们提出了大量未发表的工作，该作品表明了AGO连接酶在蝇胚胎气管系统的有丝裂后形态发生中的新作用，这是一个类似于人类脉管系统的上皮管的分支网络，该网络类似于人类脉管系统，该脉管系统通过发育的胚胎导管氧气。我们假设AGO通过一个新的靶标在这一途径中起作用：气管蛋白（TRH），低氧诱导因子（HIF）-1α-1α转录因子家族，该家族激活成纤维细胞生长因子（FGF）途径，是果蝇和血管中的果蝇和血管发展中的毛骨管发育的调节剂。在特定目标1中，我们试图检验我们的初步数据提出的假设，该假设以前结合了气管细胞中的TRH，并将其靶向降解。我们发现，AGO可以在此过程中与DVHL基因进行冗余作用，DVHL基因编码已知参与气管发育的HIF-1α泛素 - 连接酶，并且在特定的目标2中，我们建议在AGO和DVHL之间测试遗传和功能相互作用。我们还发现，成熟组织中AGO的失活能够自主诱导异位末端气管分支，这一过程通常由氧气可用性控制。因此，我们假设AGO在抑制气管分支的稳态机制中起着重要作用。我们在特定目标3中的目标是定义这一角色并阐明其分子基础。