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 胚胎发育期间的日子，这种产物经历了复杂的形态发生序列 变化导致其延长，盘绕和差异模式成对感官和非感官细胞类型 这对于听力至关重要（Groves and Fekete，2012年）。耳蜗的先天性畸形经常导致 耳聋，强调了对其发展的彻底理解的重要性（Jackler等，1987）。 我们先前描述了促进声音刺猬（SHH）信号通路的关键功能 耳囊中的腹侧身份，这对于后续的人工耳蜗生长所必需 （Riccomagno等，2002; Bok等，2007b; Brown and Epstein，2011）。鼠标缺乏SHH或 携带平滑（Smoecko）的有条件敲除（Smoecko），这是必不可少的SHH信号转导 成分，展示人工耳蜗发育不全。我们还将几个转录因子分类为关键作用 人工耳蜗发育是SHH的转录目标（PAX2，OTX2，GATA3）或效应子（GLI2，GLI3） 腹膜上皮中的信号传导。但是，尽管有这些进步，但对 SHH依赖转录因子促进人工耳蜗的生长的机制尚不清楚， 主要是因为该转录级联反应下游的基因尚未确定。 为了识别SHH信号的新目标，我们比较了对照的全基因组表达曲线 当耳蜗呈明显并发现一组有趣的SHH时 响应性基因在人工耳蜗中具有已知和以前未表征的作用的组合 形态发生。有趣的是，其中几个基因在后来的发展阶段保持其表达 在人工耳蜗的前沿域内，提高了SHH信号传导的可能性 推定感官上皮，以进行其发育的后续步骤。我们建议表征 根据以下实验计划设定的腹侧耳基因：对其时空模式进行分类 表达和对SHH信号传导的依赖性（AIM 1）；解码其顺式调节结构（AIM 2）；和 评估其对人工耳蜗发展的功能贡献（AIM 3）。这些实验的结果应 促进我们对人工耳蜗下的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。