Defining the pathological mechanisms of hereditary hearing loss

项目摘要 许多与各种形式的遗传性听力损失（HHL）相关的突变已经在遗传性耳聋中被发现。 许多基因。定义HHL基因的生理作用和突变的病理机制 在这些基因中发现的基因对于开发针对HHL的补救措施很重要。这项研究将确定 HHL基因SLC26A4和SLC26A5突变的致病性和病理机制。 SLC26A4编码阴离子转运蛋白pendrin。这种基因的改变是一种常见的 遗传性听力损失的原因，在这个基因中已经发现了300多个错义突变。在 为了确定这些突变的病理机制，重要的是要知道这些突变是如何发生的。 影响pendrin的功能以及功能表型如何与疾病表型相关。本 末端，蛋白表达，膜靶向，和阴离子转运功能的突变pendrin蛋白将 在哺乳动物细胞系中表征。结果将被映射到结构模型上， 可以获得pendrin和其它SLC 26蛋白的机理见解。大量的误解 在SLC26A4中发现的突变使得这些努力系统而彻底。 SLC26 A5编码一种基于膜的马达蛋白，普雷斯廷，其在大肠杆菌中大量表达。 OHC。它的电压驱动的运动活动，电活动，被证明是必不可少的正常耳蜗 放大然而，目前还不清楚如何在扩增过程中使用电迁移。 SLC26A5突变的病理学特征一直不明确，因为缺乏这一点。 基础知识。在这项研究中，普雷斯廷的快速运动活动的重要性将被检查 使用表达普雷斯廷的动物模型，所述普雷斯汀含有显著减缓HHL相关突变的HHL相关突变， 普雷斯廷运动动力学此外，最近在一名患者中发现了两种新的SLC26A5错义突变， 先天性听力损失的特点，以进一步了解如何普雷斯廷有助于 耳蜗放大过程和OHC维持。 疾病相关突变的功能表征不仅对于评估其 致病性，但也有利于欣赏基因的正常生理作用和定义 基因产物的分子机制。成功完成本研究， 在SLC26A4和SLC26A5中发现的突变的病理学特征。

Project Summary Numerous mutations associated with various forms of hereditary hearing loss (HHL) have been identified in many genes. Defining the physiological roles of HHL genes and the pathological mechanisms of mutations found in these genes is important for the development of remedies against HHL. This study will determine the pathogenicity and pathological mechanisms of mutations found in two HHL genes, SLC26A4 and SLC26A5. SLC26A4 encodes an anion transporter, pendrin. Alterations of this gene are one of the common causes of hereditary hearing loss, and over 300 missense mutations have been identified in this gene. In order to define the pathological mechanisms of these mutations, it is important to know how these mutations affect the function of pendrin and how the functional phenotypes correlate with disease phenotypes. To this end, protein expression, membrane targeting, and anion transport functions of mutated pendrin proteins will be characterized in a mammalian cell line. The results will be mapped onto a structural model so that mechanistic insights for pendrin and other SLC26 proteins can be obtained. The large number of missense mutations found in SLC26A4 makes these efforts systematic and thorough. SLC26A5 encodes a membrane-based motor protein, prestin, which is abundantly expressed in OHCs. Its voltage-driven motor activity, electromotility, is demonstrated to be essential for normal cochlear amplification. However, it remains unclear how electromotility is used in the amplification process. Pathological characterizations of SLC26A5 mutations have been ambiguous due to the lack of this fundamental knowledge. In this study, the importance of the rapid motor activity of prestin will be examined using an animal model expressing prestin harboring an HHL-associated mutation that significantly slows the motor kinetics of prestin. In addition, two novel SLC26A5 missense mutations recently found in a patient with congenital hearing loss will be characterized in order to further gain insights as to how prestin contributes to the cochlear amplification process and OHC maintenance. Functional characterization of disease-associated mutations is not only important for assessing their pathogenicity, but also beneficial for appreciating the normal physiological roles of genes and defining the molecular mechanisms of the gene products. Successful completion of this study allows unequivocal pathological characterization of mutations found in SLC26A4 and SLC26A5.!