Genetic Regulation of Inner Ear Formation

内耳形成的遗传调控

• 批准号: 7426432
• 负责人: Monte Westerfield
• 金额: $ 45.57万
• 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 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7426432
• 关键词: Affect; Animals; Cell physiology; Cells; Competence; Confocal Microscopy; Diploidy; Ear; Embryo; Epithelium; Ethylnitrosourea; Female; Funding; Gene Expression; Genes; Genetic; Genetic Complementation Test; Genetic Screening; Goals; Grant; Green Fluorescent Proteins; Hearing problem; Human; Induced Mutation; Labyrinth; Lateral; Learning; Link; Maps; Mediating; Molecular Cloning; Morphogenesis; Movement; Mutation; Otic Placodes; Pathway interactions; Pattern; Phenotype; Process; Regulation; Research; Signal Transduction; Specific qualifier value; Testing; Time; Tissues; To specify; Zebrafish; base; chordin; gene function; hindbrain; insight; mutant; neural plate; precursor cell; research study; response; theories; transcription factor

DESCRIPTION (provided by applicant): The long-term goal of this research is to understand how cells are specified to form the ear and how these processes are affected in human hearing diseases. The inner ear arises from the otic placode that forms at the lateral edge of the neural plate adjacent to the hindbrain. Current theories suggest that inductive signals from neighboring tissues are specify formation of the placode. However, it is unknown how cells are allocated to the placode or how they respond to the inductive signals that trigger their differentiation into the ear. Previous studies identified and analyzed two sets of transcription factor pairs, DIx3b/4b and Sox9a/9b that interact in a genetic pathway to specify otic placode cells. This pathway is regulated by Fgf3/8 signals from the adjacent hindbrain. The proposed studies will test the hypothesis that DIx3b/4b function is required for cells to become competent to respond to Fgf3/8 inductive signaling and that Fgf3/8 directs convergence and epithelialization of otic precursor cells. The proposed studies will test whether DIx3b/4b is sufficient for otic competence by examining whether ectopic Fgf3/8 induces placodes only where DIx3b/4b is expressed and whether Fgf3/8 beads induce otic markers in cells that normally Inever contribute to the if cells forced to DIx3b/4b. To learn how DIx3b/4b is ear, these ectopic are express expression regulated by factors that control dorsoventral patterning; functions of Bmps, Chordin and their downstream targets will be altered. These experiments will provide a mechanistic understanding of how cells become competent to form the ear. The proposed studies will test whether Fgf3/8 directs the morphogenetic movements and epithelialization of otic precursor cell. They will test whether Fgf3/8 is required for these processes by examining embryos in which Fgf3/8 function is blocked by mutation and morpholino treatment. They will test whether Fgf3/8 is sufficient by learning whether Fgf3/8 beads induce ectopic convergence and/or epithelialization. These experiments will elucidate the link between induction and cellular morphogenesis and provide new insights into how cells are specified to form the ear. A genetic screen of mutant phenotypes will identify additional genes required for induction of the otic placode. These mutations will be characterized phenotypically with mosaic analyses and gene expression analyses in whole-mount embryos and with microarrays to learn how each gene functions, when function is critical and in which cells function is required. The mutations will be characterized genetically by mapping, by complementation testing with existing mutations, and by molecular cloning. This analysis will identify, on the basis of their functions, the critical genes required for formation of the otic placodes.

描述（由申请人提供）：这项研究的长期目标是了解细胞如何形成耳朵，以及这些过程如何在人类听力疾病中受到影响。内耳起源于在邻近后脑的神经板外侧边缘形成的耳板。目前的理论表明，来自邻近组织的感应信号特定于基板的形成。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感应信号。先前的研究鉴定并分析了两组转录因子对 DIx3b/4b 和 Sox9a/9b，它们在遗传途径中相互作用以指定耳基板细胞。该通路受邻近后脑的 Fgf3/8 信号调节。拟议的研究将检验以下假设：细胞需要 DIx3b/4b 功能才能响应 Fgf3/8 诱导信号传导，并且 Fgf3/8 指导耳前体细胞的会聚和上皮化。 拟议的研究将通过检查异位 Fgf3/8 是否仅在 DIx3b/4b 表达的地方诱导基板，以及 Fgf3/8 珠子是否在细胞中诱导耳标记物来测试 DIx3b/4b 是否足以提高耳能力，而这些细胞通常不会对被迫 DIx3b/4b 的细胞产生影响。为了了解 DIx3b/4b 如何成为耳朵，这些异位表达是受控制背腹模式的因素调节的； Bmp、Chordin 及其下游靶点的功能将发生改变。这些实验将从机制上理解细胞如何能够形成耳朵。 拟议的研究将测试 Fgf3/8 是否指导耳前体细胞的形态发生运动和上皮化。他们将通过检查 Fgf3/8 功能被突变和吗啉代治疗阻断的胚胎来测试这些过程是否需要 Fgf3/8。他们将通过了解 Fgf3/8 珠是否诱导异位汇聚和/或上皮化来测试 Fgf3/8 是否足够。这些实验将阐明诱导和细胞形态发生之间的联系，并为细胞如何形成耳朵提供新的见解。 突变表型的遗传筛选将鉴定诱导耳基板所需的其他基因。这些突变将通过整体胚胎中的镶嵌分析和基因表达分析以及微阵列来表征，以了解每个基因如何发挥作用、何时功能至关重要以及需要​​哪些细胞发挥作用。将通过作图、与现有突变的互补测试以及分子克隆来对突变进行遗传表征。该分析将根据其功能识别形成耳基板所需的关键基因。