Cyr J L, Bell A M, Hudspeth A J
Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10021-6399, USA.
Proc Natl Acad Sci U S A. 2000 Apr 25;97(9):4908-13. doi: 10.1073/pnas.070050797.
Extensive biochemical characterization of cells in the inner ear has been hampered by a lack of tools with which to identify inner-ear proteins. By using a single-chain antibody fragment isolated from a bacteriophage-displayed library, we have identified a cytokeratin that is abundant in nonsensory cells of the frog inner ear. Although the progenitors of hair cells exhibit strong immunoreactivity to this cytokeratin, the signal declines in immature hair cells and vanishes as the cells mature. The correlation between diminished immunoreactivity and hair-cell differentiation indicates that the cytokeratin is down-regulated during the transition from a nonsensory to a sensory cell and suggests that the marker is an early index of hair-cell differentiation.
内耳细胞广泛的生化特性分析一直受到缺乏鉴定内耳蛋白质工具的阻碍。通过使用从噬菌体展示文库中分离出的单链抗体片段，我们鉴定出一种在青蛙内耳非感觉细胞中大量存在的细胞角蛋白。尽管毛细胞的祖细胞对这种细胞角蛋白表现出强烈的免疫反应性，但信号在未成熟毛细胞中减弱，并在细胞成熟时消失。免疫反应性降低与毛细胞分化之间的相关性表明，细胞角蛋白在从非感觉细胞向感觉细胞转变的过程中被下调，这表明该标记物是毛细胞分化的早期指标。
