AN ANALYSIS OF THE LMX1A (DREHER) MUTANT INNER EAR

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 子项目的主要研究者可能是由其他来源提供的， 包括其他NIH来源。 列出的子项目总成本可能 表示子项目使用的中心基础设施的估计数量， NCRR赠款不直接向子项目或子项目工作人员提供资金。 我们对耳毛细胞、感觉神经元和支持细胞发育的分子基础的理解已经取得了巨大的进展。 然而，几乎没有基础前庭和耳蜗组织发生之间的分子区别。 我们的Lmx 1a空（德雷尔）小鼠的初步数据表明一个戏剧性的影响相比，Corti器官的顶端一半的基础上的组织发生：前者假设前庭器官样的组织发生，而后者开发一个干扰，但可识别的器官的Corti表型。 本申请将探索这一发现，以进一步我们对Corti器官特异性组织发生的分子理解。 在目的1中，我们将使用原位杂交和免疫组织化学在光镜和电镜水平上表征Lmx 1a缺失耳表型，以检测细胞特异性缺陷（例如，SOX 2、PROX1）。 在目标2中，我们将使用ISH检查Lmx 1a表达模式，并通过比较通常被认为对耳蜗发育重要或在耳蜗中独特表达的基因（Gata 3，Fgf 8，Fgf 10）的表达，扩展我们对无效表型的分子基础的理解。最后，在目标3中，我们将采用微阵列方法直接比较Lmx 1a null与野生型同窝仔的顶端/基底耳蜗和球囊中的基因表达。 这些目标将提供新的见解的前庭器官样表型的基底耳蜗的Lmx 1a突变体的分子基础，并通过扩展，进入器官的Corti histogenesis的分子基础。 这种理解将是重要的，试图恢复柯蒂器官从耳蜗退化的终末期的平坦上皮。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our understanding of the molecular basis of hair cell, sensory neuron and supporting cell development in the ear has seen dramatic progress. However, there is almost no basis for a molecular distinction between vestibular and cochlear histogenesis. Our preliminary data on Lmx1a null (Dreher) mice indicate a dramatic effect on the histogenesis of the basal as compared to the apical half of the organ of Corti: the former assumes a vestibular organ-like histogenesis whereas the latter develops a disturbed but recognizable organ of Corti phenotype. The present application will explore this finding to further our molecular understanding of organ of Corti-specific histogenesis. In Aim 1 we will characterize the Lmx1a null ear phenotype at the light- and electron microscopic level using in situ hybridization and immunohistochemistry to detect cell specific defects (e.g., SOX2, PROX1). In Aim 2 we will examine the Lmx1a expression pattern using ISH and expand our understanding of the molecular basis for the null phenotype by comparing the expression of genes generally considered important for cochlear development or uniquely expressed in the cochlea (Gata3, Fgf8, Fgf10). Finally, in Aim 3, we will employ a microarray approach to directly compare gene expression in the apical/basal cochlea and saccule of the Lmx1a null with that in wildtype littermates. These aims will provide new insight into the molecular basis of the vestibular organ-like phenotype of the basal cochlea of the Lmx1a mutant and, by extension, into the molecular basis of organ of Corti histogenesis. This understanding will be important in attempts to restore the organ of Corti from the flat epithelium of end-stage of cochlear degeneration.