Type IX collagen is crucial for normal hearing
Type IX collagen is crucial for normal hearing
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IX 型胶原蛋白对正常听力至关重要
DOI：
10.1016/j.neuroscience.2005.01.013
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Usami, S
中科院分区：
文献类型：
--
作者：
Asamura, K;Abe, S;Usami, S
cDNA芯片分析显示COL9A1和COL9A3在人内耳中高表达，提示IX型胶原在内耳中具有重要的功能作用。本研究通过实时荧光定量PCR进一步证实了IX型胶原基因在小鼠内耳中的存在。免疫细胞化学分析还发现，IX型胶原分布在被膜中，与II型胶原共定位，表明IX型胶原可能有助于II型胶原分子的三维整合结构。通过听觉脑干反应评估显示，col9a1基因靶向破坏的小鼠出现听力损失，这表明IX型胶原在维持正常听力方面发挥了重要作用。光镜下发现敲除小鼠被膜形态异常，电镜下证实胶原原纤维组织紊乱。在IX型胶原敲除小鼠的被膜中，一种针对II型胶原的抗体未能检测到II型胶原，提示缺乏IX型胶原可能会影响II型胶原分子的三维结构。这些发现表明，编码IX型胶原蛋白每条链的基因可能在听觉系统中履行与被膜相关的重要功能。(c) 2005 IBRO。Elsevier Ltd.出版。版权所有。
cDNA microarray analysis indicated that COL9A1 and COL9A3 are highly expressed in the human inner ear, suggesting that type IX collagen has a crucial functional role in the inner ear. This study further confirmed, by means of real-time PCR, the presence of collagen type IX genes in the mouse inner ear. Immunocytochemical analysis also revealed that type IX collagen is distributed in the tectorial membrane, where it co-localizes with type II collagen, indicating that type IX collagen may contribute to the three-dimensional integrated structure of type II collagen molecules. Mice with targeted disruption of the col9a1 gene were shown through assessment by auditory brain stem response to have hearing loss, suggesting an important role of type IX collagen in maintaining normal hearing. At the light microscopic level, the tectorial membrane of knockout mice was found to be abnormal in shape, and electron microscopy confirmed disturbance of organization of the collagen fibrils. An antibody against type II collagen failed to detect type II collagen in the tectorial membrane of type IX collagen knock-out mice, suggesting that a lack of type IX collagen may affect the three-dimensional structure of type II collagen molecules. These findings indicate that genes encoding each chain of type IX collagen may fulfill an important function associated with the tectorial membrane in the auditory system. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.