EMBRYONIC DORSOVENTRAL POLARITY IN DROSOPHILA

果蝇胚胎背腹极性

• 批准号: 6546804
• 负责人: CARL HASHIMOTO
• 金额: $ 2.49万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6546804
• 关键词: Drosophilidae; biological signal transduction; cell membrane; cellular polarity; early embryonic stage; enzyme activity; gene mutation; genetically modified animals; immunoprecipitation; invertebrate embryology; protein structure function; serine proteinases; western blottings

DESCRIPTION: (Verbatim from the applicant's abstract) Dorsoventral polarity of the Drosophila embryo is established by local activation of the Toll signaling pathway. The membrane receptor Toll appears to be activated by an extracellular ligand that is localized to the ventral side of the embryo. The Toll ligand is generated by a proteolytic processing reaction which requires four members of the serine protease family encoded by the nudel, gastrulation defective (gd), snake, and easter genes. Earlier genetic studies suggested that these proteases act in a sequential activation cascade in which the final protease processes the Toll ligand precursor, and that activation of proteases in this cascade is ventrally localized, thereby spatially restricting production of the Toll ligand. Our more recent studies suggest that the pathway producing the Toll ligand is regulated at multiple steps so that the Toll ligand is generated at an appropriate level and at a defined time and space during embryonic development. Our major goal is to understand how the proteases required to produce the Toll ligand are organized into a pathway and how they are activated and regulated. Our specific aims are: 1) To test if the proteases act in a sequential activation cascade and if the activation of any of the proteases is spatially regulated, by biochemica1 analysis of the proteases in vivo; 2) To determine if the proteases are activated on the embryo surface and if activation is spatially restricted, using immunolocalization methods; 3) To decipher the role of the GD protein in the pathway, through a combination of molecular genetic and biochemical experiments; and 4) To identify factors that spatially control the activity of the Snake and Easter proteases, using biochemical and genetic approaches. Recent studies suggest that the ancestral role of the Toll signaling pathway is in host defense, to recognize and signal the presence of microbial pathogens, and is shared by the immune systems of insects and mammals. The signal that acts as the ligand for Toll in mammalian immunity, or how this signal is generated, is not known. Thus, the information obtained from our proposed studies should be of significant relevance for addressing the question of how the Toll signaling pathway is activated during the immune response.

描述：（逐字摘自申请人摘要） 果蝇胚胎是通过Toll信号的局部激活建立的 通路膜受体Toll似乎被细胞外的 位于胚胎腹侧的配体。Toll配体是 由蛋白水解加工反应产生，该反应需要四个成员， 由裸蛋白编码的丝氨酸蛋白酶家族，原肠胚形成缺陷型（GD）， 蛇和复活节基因早期的遗传学研究表明，这些蛋白酶 在一个连续的激活级联中起作用 Toll配体前体，且在该级联中蛋白酶活化被 腹侧定位，从而在空间上限制Toll的产生 配体。我们最近的研究表明，产生Toll的途径 在多个步骤中调节Toll配体，使得Toll配体在多个步骤中产生。 在胚胎发育期间， 发展我们的主要目标是了解蛋白酶是如何 产生Toll配体被组织成一个途径，以及它们是如何被激活的 和监管。我们的具体目标是：1）测试蛋白酶是否在一个 连续激活级联，并且如果任何蛋白酶的激活是 通过体内蛋白酶的生物化学分析进行空间调节; 2） 确定蛋白酶是否在胚胎表面被激活， 使用免疫定位方法，激活在空间上受到限制; 3） 通过结合以下方法来破译GD蛋白在通路中的作用： 分子遗传学和生物化学实验;和4）确定因素， 空间控制蛇和复活节蛋白酶的活性，使用 生物化学和遗传学方法。最近的研究表明，祖先 Toll信号通路的作用是在宿主防御中，识别和传递信号， 微生物病原体的存在，并由免疫系统共享， 昆虫和哺乳动物。在哺乳动物中作为Toll配体的信号 免疫力或这种信号是如何产生的尚不清楚。因此，信息 从我们提出的研究中获得的信息应该与以下方面具有重要意义： 解决了Toll信号通路如何被激活的问题， 免疫反应。