OTOCONIA DEVELOPMENT AND MAINTENANCE

描述（由申请人提供）：我们的重力感和线性加速度对空间定位和平衡至关重要。这种感觉是通过刺激前庭毛细胞介导的，前庭毛细胞是通过耳石对内耳感觉上皮的移位来实现的。耳锥相关的平衡障碍和头晕是影响美国600多万成年人的重要健康问题。这个问题在老年人中更严重。尽管鉴定了许多参与耳石/耳石异常的蛋白质，但无论是蛋白质的功能还是晶体形成的机制或过程都没有定义。使用基因靶向策略，我们已经证明，占主导地位的哺乳动物耳锥蛋白，耳锥蛋白-90/95（OC 90），是一个重要的组织者的有机基质的耳锥招募其他成分的钙化。oc 90基因敲除小鼠具有数量大大减少的巨大“耳锥”，这导致平衡缺陷。该提案旨在进行深入的定量表达研究和蛋白质生化分析，以探讨Oc 90和耳蛋白在提供最佳耳石钙化中的作用，并确定对耳石空间特异性发育至关重要的因素。我们将严格测试的假设，OC 90专门招募一个重要的耳锥蛋白，耳突蛋白，耳锥基质的形成和播种，并确定这种特异性的机制。然后，我们将使用现有的o> tectorin无效小鼠来产生Oc 90/a-tectorin的双敲除，以测试这两种蛋白质由于它们与耳蛋白的相互作用而在耳石接种中相互促进的假设。然后我们将开始研究，以确定因素（S）是负责耳石的空间特异性发展。这些研究将确定耳石形成中一些关键成分的作用并提供其机制。

DESCRIPTION (provided by applicant): Our sense of gravity and linear acceleration is critical for spatial orientation and balance. Such sense is mediated by stimulation of vestibular hair cells by the displacement of otoconia against the sensory epithelium in the inner ear. Otoconia-related balance disorders and dizziness are a significant health issue that affects over 6 million adults in the United States. This problem is worse in the elderly. Despite the identification of a number of proteins involved in otoconia/otolith abnormalities, neither the functions of the proteins nor the mechanisms or processes of crystal formation are defined. Using a gene targeting strategy, we have demonstrated that the predominant mammalian otoconial protein, otoconin-90/95 (as Oc90), is an essential organizer of the organic matrix of otoconia by recruiting other components important for calcification. Oc90 null mice have giant "otoconia" with a greatly reduced number, which leads to balance deficits. This proposal is designed to perform in- depth quantitative expression studies and protein biochemical analyses to address the roles of Oc90 and otolin in providing optimal otoconia calcification and to identify factors critical for the spatial specific development of otoconia. We will rigorously test the hypothesis that Oc90 specifically recruits an important otoconin, otolin, for otoconia matrix formation and seeding and identify the mechanism underlying such specificity. We will then use the existing o> tectorin null mice to generate double knockouts of Oc90/a-tectorin to test the hypothesis that these two proteins facilitate each other in otoconia seeding due to their mutual interactions with otolin. We will then begin studies to identify factor(s) that are responsible for the spatial specific development of otoconia. These studies will define the roles of and provide a mechanism for some critical components in determining otoconia formation.