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方向和平衡至关重要。这种感觉是通过内耳耳膜位移对感觉上皮的前庭毛细胞的刺激介导的。耳部相关的平衡障碍和头晕是一个重要的健康问题，影响着美国600多万成年人。这个问题在老年人中更为严重。尽管已经发现了许多与耳石异常有关的蛋白质，但这些蛋白质的功能和晶体形成的机制或过程都没有明确的定义。使用基因靶向策略，我们已经证明了主要的哺乳动物耳锥蛋白otoconin-90/95（作为Oc90），通过招募其他对钙化重要的成分，是耳锥有机基质的重要组织者。Oc90缺失小鼠有巨大的“耳孔”，数量大大减少，导致平衡缺陷。本研究旨在进行深入的定量表达研究和蛋白质生化分析，以解决Oc90和耳垢蛋白在提供最佳耳垢钙化中的作用，并确定耳垢空间特异性发展的关键因素。我们将严格检验Oc90特异性招募一种重要的耳膜蛋白——耳托蛋白，用于耳膜基质的形成和播种的假设，并确定这种特异性的机制。我们将使用现有的o > tectorin零老鼠产生双重淘汰赛Oc90 / a-tectorin测试假设这两个蛋白促进彼此otoconia播种与otolin由于他们相互交互。然后，我们将开始研究确定导致耳聋空间特异性发展的因素。这些研究将确定耳郭形成过程中一些关键成分的作用并提供一个机制。

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.