Evaluation of an independent prestin mouse model derived from the 129S1 strain
Evaluation of an independent prestin mouse model derived from the 129S1 strain
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DOI：
10.1159/000106481
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发表时间：
2007-01-01
影响因子：
1.6
通讯作者：
Dallos, P.
中科院分区：
文献类型：
--
作者：
Cheatham, M. A.;Zheng, J.;Dallos, P.
使用 prestin 敲除小鼠的研究表明，外毛细胞 (OHC) 运动蛋白的去除与敏感性、频率选择性和体细胞电动性的丧失有关。在这里，我们提供了从另一个商业化生产的 prestin 小鼠模型获得的数据。圆窗的体内电记录表明，该表型与圣裘德儿童研究医院 Zuo 小组产生的原始敲除表型相似。因此，复合动作电位 (CAP) 阈值以频率相关方式移动，并且 12 kHz 时的 CAP 调谐曲线对于 3 至 18 kHz 之间的掩蔽频率是平坦的。尽管 6 kHz 的 CAP 输入输出函数在低电平时显示出灵敏度的变化，但在高电平时响应接近野生型幅度，其中耳蜗放大器的影响较小。为了确认灵敏度和频率选择性的丧失是由于 prestin 的丢失造成的，我们使用 prestin 抗体进行了免疫组织化学分析。纯合突变小鼠的耳蜗节段没有显示出荧光，而野生型小鼠则显示出针对 OHC 侧膜的荧光信号。使用LDS-PAGE/Western印迹分析证实prestin蛋白不存在。这些结果表明功能表型的丧失与 prestin 蛋白的丧失相关。 prestin蛋白的缺乏也会导致OHC长度缩短至与野生型相似的60%，这与Liberman小组之前报道的类似。 prestin 蛋白缺失与耳蜗功能异常之间的联系证实了最初的敲除，并证明了 OHC 运动功能在听觉周围的重要性。版权所有 c 2007 S. Karger AG，巴塞尔。
Studies using the prestin knockout mouse indicate that removal of the outer hair cell (OHC) motor protein is associated with loss of sensitivity, frequency selectivity and somatic electromotility. Here we provide data obtained from another prestin mouse model that was produced commercially. In vivo electrical recordings from the round window indicate that the phenotype is similar to that of the original knockout generated by the Zuo group at St. Jude Children's Research Hospital. Hence, compound action potential ( CAP) thresholds are shifted in a frequency-dependent manner and CAP tuning curves at 12 kHz are flat for masker frequencies between 3 and 18 kHz. Although CAP input-output functions at 6 kHz show a shift in sensitivity at low levels, responses approach wild-type magnitudes at high levels where the cochlear amplifier has less influence. In order to confirm that the loss of sensitivity and frequency selectivity is due to loss of prestin, we performed immunohistochemistry using a prestin antibody. Cochlear segments from homozygous mutant mice showed no fluorescence, while wild-type mice displayed a fluorescent signal targeted to the OHC's lateral membrane. Absence of prestin protein was confirmed using LDS-PAGE/Western blot analysis. These results indicate that the loss of function phenotype is associated with loss of prestin protein. Lack of prestin protein also results in a shortening of OHC length to similar to 60% of wild-type, similar to that reported previously by Liberman's group. The linkage shown between the loss of prestin protein and abnormal cochlear function validates the original knockout and attests to the importance of OHC motor function in the auditory periphery. Copyright c 2007 S. Karger AG, Basel.