AN ANALYSIS OF THE LMX1A (DREHER) MUTANT INNER EAR

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 我们对耳朵毛细胞、感觉神经元和支持细胞发育的分子基础的了解取得了巨大的进展。然而，前庭组织发生和耳蜗组织发生之间几乎没有分子区别的基础。我们在Lmx1a空(Dreher)小鼠上的初步数据表明，与Corti器官的顶端半部分相比，Lmx1a Null(Dreher)小鼠的基底器官的组织发生具有显著的影响：前者呈现前庭器官样的组织发生，而后者发展出受干扰但可识别的Corti表型器官。目前的应用将探索这一发现，以加深我们对Corti特异性组织发生器官的分子理解。在目标1中，我们将利用原位杂交和免疫组织化学检测细胞特异性缺陷(例如，SOX2、PROX1)，在光镜和电子显微镜水平上表征Lmx1a缺失的耳朵表型。在目标2中，我们将使用ISH技术研究Lmx1a的表达模式，并通过比较通常被认为对耳蜗发育重要或在耳蜗组织中唯一表达的基因(GATA3、Fgf8、Fgf10)的表达，扩大我们对零表型的分子基础的理解。最后，在目标3中，我们将使用微阵列方法直接比较Lmx1a缺失的耳蜗顶端/基底部和球囊中的基因表达与野生型斜生后代的基因表达。这些目的将为Lmx1a突变体的基耳蜗前庭器官样表型的分子基础提供新的见解，进而为Corti组织发生器官的分子基础提供新的见解。这一认识对于从终末期耳蜗变性的扁平上皮修复Corti器官的尝试将是重要的。

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.