Role of connexins in cochlear functions

连接蛋白（Cxs）是构成差距连接（GJ）的膜蛋白，其提供调节的免疫调节。 细胞间离子通道（例如，K+、Ca++）和生物化学（例如，营养素和信号分子） 联轴节.遗传学研究已经将Cx基因中的100多个突变与大部分的 语前非综合征性耳聋尽管他们在听力方面很重要，但我们对他们的作用知之甚少。 Cxs在耳蜗中发挥作用。我们的长期目标是了解维持 在哺乳动物耳蜗中的稳态，特别是蛋白质的Cx家族在 耳蜗在这个为期5年的项目中，我们计划利用多学科的方法进行三个系列的实验。 一种检验异源多聚体GJ组装介导的生化偶联假说的方法 Cx 26和Cx 30的表达是小鼠正常听力所必需的。首先，我们将使用体外 系统来研究与耳聋相关的一些人类Cx 26突变是否特异性影响 耳蜗GJ的生物化学渗透性。由于大多数耳蜗GJ由异源多聚体组成， 因此，缺失一个Cx基因并不一定消除GJ通道， 耳蜗我们的第二系列实验将研究GJ通道是否仍然具有功能， Cx 30-/-小鼠耳蜗中的离子渗透。使用原位制备和生化分析，我们将 测试野生型GJ分子构型的变化是否是导致Cx 30-/-耳聋的原因。 小鼠在最后一系列的实验中，我们将通过转基因表达来挽救Cx 30-/-小鼠的听力。 Cx 30或Cx 26在Cx 30基因调控机制的空间和时间控制下， 整合在细菌人工染色体中。这些在Cx 30-/-小鼠中基因重建的GJ包括 野生型Cx的天然或非天然混合主要影响细胞间的生化偶联。结果 从第三系列实验中获得的结果将进一步在体内验证我们的假设。任何有效的设计 Cx突变引起的感音神经性听力损失患者的治疗取决于我们的 了解Cxs在耳蜗中的作用。随着具体目标的成功实现， 在这里提出，我们希望显着推进我们的知识介导的细胞间通讯 GJs在耳蜗和提高我们的能力，以帮助数以百万计的聋人患者在未来。

Connexins (Cxs) are membrane proteins constituting the gap junctions (GJs), which provide a regulated conduit for intercellular ionic (e.g., K+, Ca++) and biochemical (e.g., nutrients and signaling molecules) couplings. Genetic studies have linked more than 100 mutations in Cx genes to a large proportion of prelingual nonsyndromic deafness. Despite their importance in hearing, we know very little about the role Cxs play in the cochlea. Our long-term goal is to understand the molecular mechanisms maintaining homeostasis in the mammalian cochlea, especially the role played by the Cx family of proteins in the cochlea. In this 5-year project, we plan to conduct three series of experiments utilizing a multidisciplinary approach to test the HYPOTHESIS that biochemical coupling mediated by heteromultimeric GJs assembled from Cx26 and Cx30 in the cochlea is required for normal hearing in mice. First, we will use an in vitro system to investigate whether some human Cx26 mutations linked to deafness specifically affect biochemical permeability of cochlear GJs. Since most cochlear GJs are constituted by heteromultimeric assembly of Cx26 and Cx30, therefore deleting one Cx gene does not necessarily eliminate GJ channels in the cochlea. Our second series of experiments will investigate whether GJ channels are still functional for ionic permeation in the cochlea of Cx30-/- mice. Using in situ preparations and biochemical assays, we will test whether a change in the molecular configuration of wild type GJs are responsible for deafness in Cx30-/- mice. In the last series of experiments we will rescue the hearing of Cx30-/- mice by transgenic expressions of either Cx30 or Cx26 under the spatial and temporal controls of the Cx30 gene regulatory mechanisms integrated in bacterial artificial chromosome. These genetically reconstituted GJs in Cx30-/- mice consisting of native or non-native mixings of wild type Cxs mainly affect intercellular biochemical couplings. Results obtained from the third series of experiments will further test our hypothesis in vivo. Design of any effective treatment for patients suffering from sensorineural hearing loss caused by Cx mutations depends on our understanding of the role Cxs play in the cochlea. With successful implementation of the specific aims proposed here, we hope to significantly advance our knowledge of intercellular communication mediated by GJs in the cochlea and improve our ability to help millions of deaf patients in the future.