Spatiotemporal regulation of collective cell behaviors in Drosophila

果蝇集体细胞行为的时空调控

• 批准号: 10580778
• 负责人: Denise J. Montell
• 金额: $ 48.05万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10580778
• 关键词: Adhesives; Animal Model; Anterior; B-Lymphocytes; Basement membrane; Cell Communication; Cell Polarity; Cell Shape; Cell model; Cells; Cellular Morphology; Chemicals; Complex; Cytoskeleton; Development; Disease; Drosophila genus; Eating; Epithelial Cells; Exhibits; Family; Funding; Genes; Genetic; Genetic Models; Germ-Line Mutation; Goals; Guanosine Triphosphate Phosphohydrolases; Health; Hematopoietic; Human; Hyperactivity; Imaging Techniques; Immune; Immunologic Deficiency Syndromes; Investigation; Macrophage; Mediating; Molecular; Monomeric GTP-Binding Proteins; Mutation; Natural regeneration; Neoplasm Metastasis; Normal tissue morphology; Nurses; Oocytes; Oogenesis; Ovary; Pathway interactions; Patients; Phagocytes; Phagocytosis; Process; Property; Public Health; Regulation; Role; Signal Transduction; Structure; Surface; System; T-Lymphocyte; Testing; Work; cancer cell; cancer immunotherapy; cancer therapy; cell behavior; cell killing; cell motility; cell type; chronic infection; cohesion; constitutive expression; egg; fly; follow-up; human disease; immune system function; improved; in vivo; in vivo Model; inhibitor; insight; migration; novel; novel strategies; optogenetics; photoactivation; premature; programs; protein complex; recruit; rho; spatiotemporal; tumor

Normal tissue development and tumor metastasis require extensive cell movements, and border cell migration in the Drosophila ovary provides a powerful in vivo model. Border cells migrate as a group of two different cell types, a pair of non-migratory polar cells in the center that recruit 6-8 epithelial cells to surround and carry them between nurse cells to the developing oocyte, in a structure called an egg chamber. Using this system, we first discovered the in vivo role of the 21kD GTPase Rac in protrusion and migration, then showed that photoactivation of Rac in one cell could steer the entire cluster. For more than two decades though, we were puzzled that expression of constitutively active Rac in border cells seemed to destroy the entire egg chamber. During the current funding period, we solved this longstanding mystery. We discovered that border cells expressing active Rac kill the nurse cells. Anterior follicle cells normally engulf and kill nurse cells late in oogenesis, and we propose that active Rac prematurely activates this program. A similar mechanism may explain otherwise mysterious immune deficiencies in human patients. Here we propose to continue our exciting investigation of the spatiotemporal control of Rac-mediated cell migration and engulfment in Drosophila. In Aim 1 we propose to elucidate the mechanisms of Rac-mediated cell killing. Taking advantage of the border cell model, we will test the functional effects of each of the known activating Rac mutations that cause immunodeficiencies in patients. We will test the hypothesis that border cells expressing active Rac prematurely activate the normal developmental killing program, and we will define more precisely the role of Rac within the molecular pathway. We will investigate how just six cells can destroy an entire egg chamber, and we will identify the chemical, physical, and adhesive properties that govern target cell selection. In Aim 2, we propose to follow up on our discovery that a basally localized Rac activator is required for border cell cluster cohesion and migration. We will elucidate its relationship to basolateral complex proteins and test whether its primary function is to localize Rac activity to basal surfaces. We will test the hypothesis that basal Rac activity is required to generate basal protrusions that in turn coordinate collective cell behavior. In Aim 3, we will follow up on a screen in which we have identified Rho family activators and inhibitors required in border cells. We propose that border cells require elaborate spatiotemporal control of Rac due to their needs to: maintain apicobasal polarity despite being detached from basement membrane, extend and retract forward-directed protrusions, maintain cohesion under strain, and inhibit inappropriate protrusion. Our ultimate goal is the decipher the Rac regulatory network.

正常的组织发育和肿瘤转移需要广泛的细胞运动和边缘细胞 果蝇卵巢中的迁移提供了一个强大的体内模型。边界像元以两个一组的形式迁移 不同的细胞类型，中心的一对非迁移性极细胞招募6-8个上皮细胞包围 并将它们在哺乳细胞之间运送到发育中的卵母细胞，形成一种称为卵室的结构。vbl.使用 在这个系统中，我们首先在体内发现了21kD GTPase Rac在突起和迁移中的作用，然后 表明在一个细胞中RAC的光激活可以引导整个集群。二十多年来 然而，我们感到困惑的是，在边界细胞中结构性活跃的RAC的表达似乎破坏了 整个卵室。在目前的融资期间，我们解开了这个长期存在的谜团。我们发现 表达活性RAC的边界细胞杀死了护理细胞。前滤泡细胞通常吞噬并杀死护士 细胞在卵子发生的晚期，我们认为活性的RAC过早地激活了这一程序。一种类似的 这一机制或许可以解释人类患者的神秘免疫缺陷。在此，我们建议 继续我们对RAC介导的细胞迁移的时空控制的令人兴奋的研究 吞噬在果蝇体内。在目标1中，我们建议阐明RAC介导的细胞杀伤的机制。 利用边界细胞模型，我们将测试每个已知激活的功能效果 导致患者免疫缺陷的RAC突变。我们将测试边界细胞的假设 过早表达活跃的RAC激活正常的发育杀伤程序，我们将定义 更准确地说，RAC在分子途径中的作用。我们将研究仅仅六个细胞是如何 摧毁整个卵室，我们将确定化学、物理和粘附性 管理目标单元格选择。在目标2中，我们建议跟进我们的发现，即基本本地化的RAC 边界细胞团的凝聚和迁移需要激活剂。我们将阐明它与 并测试其主要功能是否为将Rac活性定位于 表面。我们将测试以下假设，即基础RAC活动是产生基础突起所必需的，在 反过来协调集体细胞的行为。在目标3中，我们将在一个屏幕上跟进，在该屏幕中我们已经确定 边界细胞所需的Rho家族激活剂和抑制物。我们建议边界细胞需要详细说明 RAC的时空控制，因为他们需要：在分离的情况下保持心尖基底极性 从基底膜，伸展和收缩前向突起，在张力下保持凝聚力， 并抑制不适当的突起。我们的最终目标是破译RAC监管网络。