OTOCONIA DEVELOPMENT AND MAINTENANCE

描述(申请人提供)：我们的重力感和线加速度对空间定向和平衡至关重要。这种感觉是通过耳锥对内耳感觉上皮的移位刺激前庭毛细胞来调节的。与耳鸣相关的平衡障碍和头晕是一个重大的健康问题，影响着美国600多万成年人。这一问题在老年人中更为严重。尽管已经鉴定了许多与耳石/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。利用基因打靶策略，我们通过招募其他对钙化至关重要的成分，证明了哺乳动物主要的耳锥蛋白Otoconin-90/95(如Oc90)是耳石有机基质的重要组织者。10月90号空白小鼠有巨大的“耳锥”，数量大大减少，导致平衡赤字。这项建议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Ootlin在提供最佳耳石矿化方面的作用，并确定对耳石的空间特异性发展至关重要的因素。我们将严格测试这一假设，即Oc90专门招募一种重要的耳胶原--耳胶，用于耳锥基质的形成和播种，并确定这种特异性背后的机制。然后，我们将使用现有的o&gt；tectorin基因缺失小鼠产生Oc90/a-tectorin的双重敲除，以检验这两种蛋白质在耳石播种过程中由于与耳垢相互作用而相互促进的假设。然后，我们将开始研究，以确定负责的空间特异性发展耳锥的因素(S)。这些研究将确定一些关键成分在确定耳石形成中的作用并提供机制。

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.