The mechanosensory structure of the hair cell requires clarin-1, a protein encoded by Usher syndrome III causative gene.
The mechanosensory structure of the hair cell requires clarin-1, a protein encoded by Usher syndrome III causative gene.
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毛细胞的机械感觉结构需要 clarin-1，这是一种由 Usher 综合征 III 致病基因编码的蛋白质。
DOI：
10.1523/jneurosci.0311-12.2012
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发表时间：
2012-07-11
期刊：
影响因子：
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通讯作者：
Alagramam KN
中科院分区：
文献类型：
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作者：
Geng R;Melki S;Chen DH;Tian G;Furness DN;Oshima-Takago T;Neef J;Moser T;Askew C;Horwitz G;Holt JR;Imanishi Y;Alagramam KN
clarin-1基因突变导致人类听力和视力丧失（Usher综合征III），但clarin-1在感觉毛细胞中的作用尚不清楚。预测Clarin-1是类似于四跨膜蛋白家族成员的四跨膜结构域蛋白。在clarin-1（Clrn 1 −/−）基因中携带无效突变的小鼠表现出毛细胞功能的丧失和带状突触的可能缺陷。我们使用各种体外和体内方法研究了clarin-1的作用。我们通过免疫组织化学和膜片钳记录的钙电流和膜电容的IHC，clarin-1是不是必不可少的带状突触的形成或功能。然而，耳蜗微音器电位、FM 1 -43负载和转导电流的降低表明Clrn 1 −/−小鼠耳蜗毛束功能减弱。耳蜗毛细胞的电子显微镜检查显示，一些高静纤毛和V形束中的间隙丢失，尽管静纤毛的尖端连接和楼梯排列并不主要受Clrn 1 −/−突变的影响。人clarin-1蛋白在转染的小鼠耳蜗毛细胞中表达，定位于束;然而，致病性变体p.N48K未能定位于束。为研究clarin-1中p.N48K（Clrn 1 N48 K）的体内结果而产生的小鼠模型支持我们的体外和Clrn 1 −/−小鼠数据以及CLRN 1是必需的毛束蛋白的结论。此外，Clrn 1 N48 K小鼠的耳部表型表明，它是CLRN 1 N48 K耳部疾病的有价值的模型，CLRN 1 N48 K是北美最普遍的Usher III突变。
Mutation in the clarin-1 gene results in loss of hearing and vision in humans (Usher syndrome III), but the role of clarin-1 in the sensory hair cells is unknown. Clarin-1 is predicted to be a four transmembrane domain protein similar to members of the tetraspanin family. Mice carrying null mutation in the clarin-1 (Clrn1−/−) gene show loss of hair cell function and a possible defect in ribbon synapse. We investigated the role of clarin-1 using various in vitro and in vivo approaches. We show by immunohistochemistry and patch-clamp recordings of Ca2+ currents and membrane capacitance from IHCs that clarin-1 is not essential for formation or function of ribbon synapse. However, reduced cochlear microphonic potentials, FM1-43 loading and transduction currents pointed to diminished cochlear hair bundle function in Clrn1−/− mice. Electron microscopy of cochlear hair cells revealed loss of some tall stereocilia and gaps in the v-shaped bundle, although tip-links and staircase arrangement of stereocilia were not primarily affected by Clrn1−/− mutation. Human clarin-1 protein expressed in transfected mouse cochlear hair cells localized to the bundle; however, the pathogenic variant, p.N48K, failed to localize to the bundle. The mouse model generated to study the in vivo consequence of p. N48K in clarin-1 (Clrn1N48K) supports our in vitro and Clrn1−/− mouse data and the conclusion that CLRN1 is an essential hair bundle protein. Further, the ear phenotype in the Clrn1N48K mouse suggests that it is a valuable model for ear disease in CLRN1N48K, the most prevalent Usher III mutation in North America.