GENETIC REGULATION OF INNER EAR FORMATION

内耳形成的遗传调控

• 批准号: 6630453
• 负责人: Monte Westerfield
• 金额: $ 33.25万
• 依托单位: UNIVERSITY OF OREGON
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6630453
• 关键词: biological signal transduction; cell cell interaction; cell transplantation; developmental genetics; genetic regulation; growth /development; labyrinth; mutant; point mutation; tissue mosaicism; vertebrate embryology; zebrafish

Our long term goal is to understand how cells are specified to form the ear. The inner ear arises from the otic placode. Previous studies suggest that inductive signals from neighboring tissues specify formation of the placode. However, it is unknown how cells are allocated to the placode or how they respond to the signals that trigger their differentiation into the ear. We have identified a zebrafish mutant that lacks a detectable otic placode and fails to form an ear. The mutation is a deficiency of the closely linked dlx3 and dlx7 genes. We propose to use this mutation to analyze the cellular interactions required to form the placode and the potential roles of these genes in this process. 1. We will test the hypothesis that function of the dlx3-dlx7 genes is required for formation of the ear. To learn whether expression of dlx3-dlx7 is necessary to form the ear, we will isolate point mutations in these genes. To learn whether dlx3-dlx7 expression is sufficient, we will rescue the mutant phenotype with wild-type transgenes. These experiments will elucidate the functions of dlx3-dlx7 in specification of otic placode cells. 2. We will test the hypothesis that the dlx3-dlx7 genes function to specify the competence of cells to form the ear. This hypothesis predicts the mutation should autonomously affect cells that form the placode. We will identify which cells the mutation affects by generating genetic mosaics. This analysis will tell us in which cells the dlx3-dlx7 genes normally act. We will use small groups of competent cells from wild-type hosts as probes to learn the locations of signaling cells in mutant hosts. We will then transplant wild-type cells into these locations in dlx3-dlx7 mutants at various developmental stages. These experiments will reveal which cells signal induction of the placode and at what developmental time the induction occurs. 3. We will screen for mutations in genes that encode the inductive signal and signal response system that are required to form the otic placode. We will screen for mutations that block formation of the otic placodes. We will characterize these mutations phenotypically and genetically. This analysis will identify genes on the basis of their functions in specifying the fates of cells that form the otic placodes. This application is part of an IRPG to understand the mechanisms that regulate morphogenesis and cell specification in the vertebrate inner ear.

我们的长期目标是了解细胞是如何形成耳朵的。 内耳起源于耳板。先前的研究表明，来自邻近组织的感应信号指定了基板的形成。 然而，目前尚不清楚细胞如何分配到基板或它们如何响应触发其分化为耳朵的信号。 我们发现了一种斑马鱼突变体，它缺乏可检测的耳基板并且无法形成耳朵。 该突变是紧密相连的 dlx3 和 dlx7 基因的缺陷。 我们建议利用这种突变来分析形成基板所需的细胞相互作用以及这些基因在此过程中的潜在作用。 1. 我们将检验以下假设：耳朵的形成需要 dlx3-dlx7 基因的功能。 为了了解 dlx3-dlx7 的表达是否是形成耳朵所必需的，我们将分离这些基因中的点突变。 为了了解 dlx3-dlx7 表达是否足够，我们将用野生型转基因拯救突变表型。 这些实验将阐明 dlx3-dlx7 在耳基板细胞规范中的功能。 2. 我们将检验以下假设：dlx3-dlx7 基因的功能是指定细胞形成耳朵的能力。 该假设预测突变应自主影响形成基板的细胞。 我们将通过生成基因镶嵌来识别突变影响哪些细胞。 该分析将告诉我们 dlx3-dlx7 基因通常在哪些细胞中发挥作用。 我们将使用来自野生型宿主的一小组感受态细胞作为探针来了解突变宿主中信号细胞的位置。 然后，我们将野生型细胞移植到处于不同发育阶段的 dlx3-dlx7 突变体的这些位置。这些实验将揭示哪些细胞发出基板诱导的信号以及诱导发生的发育时间。 3. 我们将筛选编码形成耳基板所需的感应信号和信号反应系统的基因突变。 我们将筛选阻止耳基板形成的突变。 我们将从表型和遗传学上描述这些突变。 该分析将根据基因在指定形成耳基板的细胞的命运方面的功能来识别基因。该应用程序是 IRPG 的一部分，旨在了解调节脊椎动物内耳形态发生和细胞规格的机制。