Correlation of expression of the actin filament-bundling protein espin with stereociliary bundle formation in the developing inner ear
Correlation of expression of the actin filament-bundling protein espin with stereociliary bundle formation in the developing inner ear
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DOI：
10.1002/cne.10944
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发表时间：
2004-01-01
影响因子：
2.5
通讯作者：
Heller, S
中科院分区：
文献类型：
--
作者：
Li, HW;Liu, H;Heller, S
脊椎动物的毛细胞因其从细胞顶端表面伸出的立体纤毛束或毛束而得名。毛束介导机械敏感性，其高度组织化的结构在机电传导和放大中起着关键作用。原型毛束由单个的立体纤毛组成，数量为50-300，取决于动物的种类和毛细胞的类型。立体纤毛的组装，特别是单排立体纤毛在发育过程中的形成，已经被详细地分析了。电镜研究表明，立体纤毛充满了刚性交联的肌动蛋白丝。单行立体纤毛的生长与肌动蛋白丝的增加和肌动蛋白丝之间的交桥数量的逐渐增加有关。最近，肌动蛋白丝束蛋白espin的突变已被证明是聋鼠毛束变性的基础，随后导致耳聋。本研究探讨了espin在鸡内耳感觉上皮中的外观和发育表达。我们发现espin表达的开始与前庭和耳蜗毛细胞中立体纤毛束的形成和生长有关。在所有类型的毛细胞中，在所有发育阶段和成年动物中，静纤毛的强烈的纺丝免疫标记与肌动蛋白丝染色是共定位的。我们对细支蛋白作为静纤毛肌动蛋白丝交联的分子标记的分析与先前的形态学研究完全一致，并暗示细支蛋白从毛束组装的起始到成熟的鸡毛细胞是毛束的重要结构成分。(C) 2003 Wiley-Liss, Inc。
The vertebrate hair cell is named for its stereociliary bundle or hair bundle that protrudes from the cell's apical surface. Hair bundles mediate mechanosensitivity, and their highly organized structure plays a critical role in mechanoelectrical transduction and amplification. The prototypical hair bundle is composed of individual stereocilia, 50-300 in number, depending on the animal species and on the type of hair cell. The assembly of stereocilia, in particular, the formation during development of individual rows of stereocilia with descending length, has been analyzed in great morphological detail. Electron microscopic studies have demonstrated that stereocilia are filled with actin filaments that are rigidly cross-linked. The growth of individual rows of stereocilia is associated with the addition of actin filaments and with progressively increasing numbers of cross-bridges between actin filaments. Recently, a mutation in the actin filament-bundling protein espin has been shown to underlie hair bundle degeneration in the deaf jerker mouse, subsequently leading to deafness. Our study was undertaken to investigate the appearance and developmental expression of espin in chicken inner ear sensory epithelia. We found that the onset of espin expression correlates with the initiation and growth of stereocilia bundles in vestibular and cochlear hair cells. Intense espin immunolabeling of stereocilia was colocalized with actin filament staining in all types of hair cells at all developmental stages and in adult animals. Our analysis of espin as a molecular marker for actin filament cross-links in stereocilia is in full accordance with previous morphological studies and implicates espin as an important structural component of hair bundles from initiation of bundle assembly to mature chicken hair cells. (C) 2003 Wiley-Liss, Inc.