EMBRYONIC DORSOVENTRAL POLARITY IN DROSOPHILA

描述：(一字不差地摘自申请人的摘要)背侧腹极 果蝇胚胎是通过局部激活Toll信号而建立的 路径。膜受体Toll似乎被细胞外激活 定位于胚胎腹侧的配体。Toll配体是 由需要四个成员的蛋白质分解处理反应产生 由Nudel编码的丝氨酸蛋白酶家族，原肠形成缺陷(Gd)， 蛇和复活节基因。早期的遗传学研究表明，这些蛋白水解酶 以顺序激活级联的方式进行操作，在该级联中，最终的蛋白酶过程 Toll配体前体，该级联中蛋白水解酶的激活 腹地本地化，从而在空间上限制通行费的生产 莱兰德。我们最近的研究表明，产生通行费的途径 配体在多个步骤中被调节，从而在 在胚胎期的适当水平和确定的时间和空间 发展。我们的主要目标是了解蛋白水解酶是如何 产生Toll配体被组织成一条途径以及它们是如何被激活的 并受到监管。我们的具体目标是：1)测试蛋白酶是否在 顺序激活级联以及如果任何一种蛋白水解酶的激活 通过体内的蛋白水解酶生化分析进行空间调控；2) 确定蛋白水解酶是否在胚胎表面被激活，以及 使用免疫定位方法，激活在空间上受到限制；3) 破译gD蛋白在该途径中的作用，通过组合 分子遗传学和生物化学实验；以及4)确定 空间控制蛇和复活节蛋白水解酶的活性，使用 生物化学和遗传方法。最近的研究表明，祖先 Toll信号通路在宿主防御、识别和信号传递中的作用 微生物病原体的存在，并由猪的免疫系统共享 昆虫和哺乳动物。哺乳动物中作为Toll配体的信号 免疫力，或这个信号是如何产生的，目前尚不清楚。因此，这些信息 从我们建议的研究中得到的结果应该对 解决Toll信号通路是如何在 免疫反应。

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.