Genomic architecture of Shh dependent cochlear morphogenesis

Shh 依赖性耳蜗形态发生的基因组结构

• 批准号: 8629843
• 负责人: DOUGLAS J EPSTEIN
• 金额: $ 41.86万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8629843
• 关键词: Antibodies; Applications Grants; Architecture; Biological Assay; Categories; Cell Cycle; Cell physiology; ChIP-seq; Chromatin; Cochlea; Cochlear duct; Complex; Congenital Abnormality; Coupled; DNA; Data Set; Dependency; Development; Disease; Ear; Embryo; Embryonic Development; Enhancers; Epithelium; Erinaceidae; Event; Exhibits; Functional disorder; Future; Gene Expression; Genes; Genomics; Goals; Hearing; Human; Knock-out; Knockout Mice; Knowledge; Labyrinth; Lead; Location; Logic; Maps; Massive Parallel Sequencing; Medial; Mitotic; Molecular; Molecular Profiling; Morphogenesis; Mus; Otic Vesicle; Pattern; Phenotype; Regulation; Reporter; Role; Sensory; Shapes; Staging; Structure; Testing; Tissues; Transgenic Organisms; Withdrawal; base; cell fate specification; cell type; chromatin immunoprecipitation; deafness; genome-wide; hedgehog signal transduction; human SMO protein; improved; inhibitor/antagonist; inner ear diseases; insight; morphogens; novel; progenitor; public health relevance; research study; response; smoothened signaling pathway; spatiotemporal; transcription factor

The mouse cochlea derives from the ventral extension of the otic vesicle. Over the course of several days during embryonic development, this outgrowth undergoes a complex sequence of morphogenetic changes resulting in its lengthening, coiling and differential patterning into sensory and nonsensory cell types that are essential for hearing (Groves and Fekete, 2012). Congenital malformations of the cochlea often lead to deafness, emphasizing the importance of a thorough understanding of its development (Jackler et al., 1987). We previously described a critical function of the Sonic hedgehog (Shh) signaling pathway in promoting ventral identity within the otic vesicle that is necessary for the subsequent outgrowth of the cochlear duct (Riccomagno et al., 2002; Bok et al., 2007b; Brown and Epstein, 2011). Mouse embryos lacking Shh, or carrying an ear conditional knockout of Smoothened (Smoecko), an essential Shh signal transduction component, exhibit cochlear agenesis. We also classified several transcription factors with key roles in cochlear development as either transcriptional targets (Pax2, Otx2, Gata3) or effectors (Gli2, Gli3) of Shh signaling within the ventral otic epithelium. However, despite these advances, a detailed understanding of the mechanism by which Shh dependent transcription factors promote cochlear duct outgrowth remains unclear, primarily since the genes acting downstream in this transcriptional cascade have yet to be determined. To identify novel targets of Shh signaling we compared the genome-wide expression profiles of control and Smoecko inner ears at E11.5, when the cochlea anlage is evident, and uncovered an intriguing set of Shh responsive genes with a combination of known and previously uncharacterized roles in cochlear morphogenesis. Interestingly, several of these genes maintain their expression at later stages of development within the prosensory domain of the cochlear duct, raising the possibility that Shh signaling is priming the presumptive sensory epithelium for subsequent steps in its development. We propose to characterize the ventral otic gene set according to the following experimental plan: classify their spatiotemporal patterns of expression and dependency on Shh signaling (Aim 1); decode their cis-regulatory architecture (Aim 2); and assess their functional contribution to cochlear development (Aim 3). The results of these experiments should advance our fundamental understanding of the molecular and cellular mechanisms underlying cochlear morphogenesis and cell fate specification within the inner ear.

小鼠耳蜗源自耳囊的腹侧延伸。在几个过程中 在胚胎发育过程中的几天里，这种生长物经历了一系列复杂的形态发生 导致其延长、卷曲和分化为感觉和非感觉细胞类型的变化 这对于听力至关重要（Groves 和 Fekete，2012）。先天性耳蜗畸形常常导致 耳聋，强调彻底了解其发展的重要性（Jackler 等，1987）。 我们之前描述了音刺猬 (Shh) 信号通路在促进 耳囊内的腹侧特征是耳蜗管随后生长所必需的 （Riccomagno 等人，2002 年；Bok 等人，2007b；Brown 和 Epstein，2011 年）。缺乏 Shh 的小鼠胚胎，或 携带 Smoothened (Smoecko) 的耳朵条件性敲除，这是一种重要的“Shh”信号转导 成分，表现出耳蜗发育不全。我们还对几种在以下过程中起关键作用的转录因子进行了分类： 耳蜗发育作为 Shh 的转录靶点（Pax2、Otx2、Gata3）或效应器（Gli2、Gli3） 腹侧耳上皮内的信号传导。然而，尽管取得了这些进步，但对 Shh 依赖性转录因子促进耳蜗导管生长的机制仍不清楚， 主要是因为在该转录级联下游起作用的基因尚未确定。 为了确定 Shh 信号传导的新靶点，我们比较了对照的全基因组表达谱 和 Smoecko 内耳在 E11.5，当耳蜗原基明显时，并发现了一组有趣的“嘘” 反应基因在耳蜗中具有已知和以前未表征的作用 形态发生。有趣的是，其中一些基因在发育后期仍保持表达 在耳蜗管的前感觉域内，提高了 Shh 信号传导启动的可能性 假定的感觉上皮用于其发育的后续步骤。我们建议描述 根据以下实验计划对腹侧耳基因集进行分类：对其时空模式进行分类 对 Shh 信号传导的表达和依赖性（目标 1）；解读其顺式监管架构（目标 2）；和 评估其对耳蜗发育的功能贡献（目标 3）。这些实验的结果应该 增进我们对耳蜗分子和细胞机制的基本理解 内耳内的形态发生和细胞命运规范。