Genetic control of postembryonic wound healing in Drosophila

描述(由申请人提供)：组织修复能力是多细胞生物体的基本属性，通常对生存至关重要。尽管它具有生物学和临床上的重要性，但启动和终止表皮伤口闭合的信号仍然不清楚，执行这一过程所需的基因也是如此。这在一定程度上是由于脊椎动物模型生物创伤修复反应的复杂性，以及组织修复在更简单的模型遗传生物中尚未得到广泛的研究，在这些生物模型中，快速基因发现和精确的基因功能分析得到了极大的便利。本课题主要研究胚胎后创面愈合的分子遗传学调控。我们的指导性假设是，存在一个保守的细胞-细胞信号事件的分子遗传程序，它启动、调节、执行和终止修复过程。为了在遗传易控的模型系统中验证这一假说，我们用果蝇幼虫建立了表皮伤口愈合试验，并证明伤口闭合需要果蝇Jun氨基末端激酶(JNK)和我们在伤口闭合突变体的初步条件遗传筛选中确定的其他八个基因。对于这个中试筛选，我们开发了转基因报告幼虫，允许实时观察伤口闭合以及可能干扰或增强这一过程的外源RNAi转基因的表皮特异性表达。我们的长期目标是使用我们独特的分析和工具来确定有效闭合伤口所需的基因互补，并确定这些基因在伤口闭合过程中的功能。我们的短期目标列举在以下特定目标中：1.验证创伤诱导的JNK信号是由PDGF/VEGF受体PVR的果蝇同源物激活的假设，PVR是我们的试点屏幕中发现的一种受体酪氨酸激酶。2.验证JNK信号通路激活启动创伤反应细胞迁移的假说。3.通过扩展我们的条件遗传筛选策略，识别和表征伤口闭合所需的新基因。该项目代表了在模型遗传有机体中对胚胎后伤口闭合进行的第一次系统研究，并具有揭示控制伤口闭合的难以捉摸的信号的巨大潜力。考虑到大多数基本过程所需的基因的保守性，我们预计这个项目将有助于我们理解脊椎动物和癌症等病理生理状态下的伤口闭合，在这些状态下，伤口愈合反应被认为被不适当地激活或调节。这项研究项目使用了一种模式遗传有机体--果蝇，以揭示胚胎后伤口愈合的基因控制，这是一个与人类健康直接相关的过程。伤口愈合是创伤和手术康复的关键，这两种情况都很常见。考虑到大多数基本生物过程所需的基因的保守，我们预计这个项目将有助于我们理解脊椎动物的伤口闭合，以及在诸如癌症和各种皮肤病等病理生理状态下，伤口愈合反应被认为被不适当地激活或调节。

DESCRIPTION (provided by applicant): The capacity for tissue repair is a fundamental property of multicellular organisms that is often critical for survival. Despite its biological and clinical importance, the signals that initiate and terminate epidermal wound closure remain obscure, as do the genes required to execute this process. This is partly due to the complexity of wound repair responses in vertebrate model organisms and the fact that tissue repair has not been studied extensively in simpler model genetic organisms where rapid gene discovery and precise analysis of gene function are greatly facilitated. This research project focuses on the molecular genetic control of postembryonic wound healing. Our guiding hypothesis is that there is a conserved molecular genetic program of cell-cell signaling events that initiates, regulates, executes, and terminates the repair process. To test this hypothesis in a genetically tractable model system we have established epidermal wound healing assays using Drosophila larvae and demonstrated that wound closure requires the Drosophila Jun N-terminal kinase (JNK) and eight other genes we identified in a pilot conditional genetic screen for wound closure mutants. For this pilot screen we developed transgenic reporter larvae that allow live visualization of wound closure as well as epidermal-specific expression of exogenous RNAi transgenes that could interfere with or enhance this process. Our long term objective is to use our unique assays and tools to identify the complement of genes required for efficient wound closure and determine the function of these genes during wound closure. Our shorter term goals are enumerated in the following specific aims: 1. to test the hypothesis that wound- induced JNK signaling is activated by the Drosophila homolog of the PDGF/VEGF receptor, PVR, a receptor tyrosine kinase identified in our pilot screen. 2. To test the hypothesis that JNK signaling pathway activation initiates cell migration in wound-responsive cells. 3. To identify and characterize novel genes required for wound closure by expanding our conditional genetic screening strategy. This project represents the first systematic study of postembryonic wound closure in a model genetic organism and has great potential for uncovering the elusive signals that control wound closure. Given the conservation of genes required for most fundamental processes we expect that this project will inform our understanding of wound closure in vertebrates and in pathophysiological states, such as cancer, where the wound healing response is thought to be improperly activated or regulated. This research project employs a model genetic organism, the fruit fly, to uncover the genetic control of postembryonic wound healing, a process of immediate relevance to human health. Wound healing is critical for recovery from trauma and surgery, both of which are common occurrences. Given the conservation of genes required for most fundamental biological processes we expect that this project will inform our understanding of wound closure in vertebrates and in pathophysiological states, such as cancer and a variety of skin diseases, where the wound healing response is thought to be improperly activated or regulated.