AN ANALYSIS OF THE LMX1A (DREHER) MUTANT INNER EAR

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 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. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 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.