Auditory Neurogenetics

描述（由申请人提供）：听觉转导主要依赖于Atp 2b 2基因（编码PMCA 2蛋白）。我们的实验室和其他人已经在小鼠和人类基因中发现了几种突变（在Tempel和Shilling，2007中进行了综述）。我们已经开发了一个等位基因系列的mallowwaddler小鼠突变体与改变Atp 2b 2，使我们能够研究逐步减少功能性PMCA 2在耳蜗中的影响。我们已经使用该等位基因系列来表明杂合部分功能丧失突变是单倍不足的（McCullough和Tempel，2004），并提供了年龄相关性听力损失（阿勒）的模型（McCullough和Tempel，2005;步行者等人，2008年）。在这个建议中，我们将增加我们的知识，PMCA 2在耳蜗中的作用，通过检查噪音诱导的听力损失（NIHL）等位基因的pwaddler。我们将开发一种新的过表达PMCA 2的小鼠品系，以观察这些小鼠是否对阿勒或NIHL具有抗性。我们还将研究PMCA 2在听觉脑干神经元中的作用。我们假设PMCA 2在调节这些快速放电神经元中的钙（Ca 2+）中起着关键作用;以前未探索过的作用，因为研究集中在毛细胞中的PMCA 2功能上。最后，我们将开发一个细胞表达系统，用于研究PMCA 2的功能。我们将使用PMCA 2的半胱氨酸扫描诱变来定义巯基试剂在细胞外应用时可以快速阻断Ca 2+泵活性的位点。除了提供对药物靶向的潜在位点的洞察之外，这应该提供一种研究PMCA 2在毛细胞（HC）转导和神经元传递中的细胞作用的方法。在一个噪音越来越大、寿命越来越长的社会中，了解与年龄相关的听力损失和噪音引起的听力损失的基因是很重要的。我们对质膜钙泵的研究表明，它定位于听觉毛细胞的静纤毛，当其功能因小鼠或人类的突变而降低时，它们会出现显著的听力损失。我们正在研究钙泵是如何工作的，希望能找到使其保护毛细胞免受损伤的方法，从而防止听力损失。

DESCRIPTION (provided by applicant): Auditory transduction depends critically on the Atp2b2 gene (encoding the PMCA2 protein). Our lab and others have identified several mutations in mouse and human genes (reviewed in Tempel and Shilling, 2007). We have developed an allelic series of deafwaddler mouse mutants with altered Atp2b2 that allow us to study the effects of stepwise reductions of functional PMCA2 in the cochlea. We have used this allelic series to show that heterozygous partial loss of function mutations are haplo-insufficient (McCullough and Tempel, 2004) and provide a model of age-related hearing loss (AHL) (McCullough and Tempel, 2005; Walker et al., 2008). In this proposal we will add to our knowledge of the role of PMCA2 in the cochlea by examining noise-induced hearing loss (NIHL) in alleles of deafwaddler. We will develop a new line of mice that over-express PMCA2 to see if these mice are resistant to AHL or NIHL. We will also study the role of PMCA2 in neurons of the auditory brainstem. We hypothesize that PMCA2 plays a critical role in regulating calcium (Ca2+) in these fast-firing neurons; a role previously unexplored because studies have focused on PMCA2 function in hair cells. Finally, we will develop a cellular expression system for studying PMCA2 function. We will use cysteine-scanning mutagenesis of PMCA2 to define sites where thiol reagents, when applied extracellularly can rapidly block Ca2+ pump activity. Besides providing insight into potential sites for drug targeting, this should provide a way to study the cellular role of PMCA2 in hair cell (HC) transduction and neuronal transmission. In an increasingly noisy and longer-lived society, knowledge of the genes contributing to age-related hearing loss and noise induced hearing loss is important. Our work on the plasma membrane calcium pump shows that it is localized to the stereocilia of the auditory hair cells and that when its function is reduced by mutations in mouse or human, they have significant hearing loss. We are studying how the calcium pump works, hoping to learn ways to make it protect hair cells from damage, thereby preventing hearing loss.