DeRosier D J, Tilney L G
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254.
J Cell Biol. 1989 Dec;109(6 Pt 1):2853-67. doi: 10.1083/jcb.109.6.2853.
The cuticular plate is a network of actin filaments found in hair cells of the cochlea. In the alligator lizard, it consists of rootlets, emanating from the stereocilia, and of cross-connecting actin filaments that anchor these rootlets. In thin sections, this network displays striking patches of 650 +/- 110-A striae. By quantitative analyses of the images, the mystery of the striae can be explained. They are due in part to the rootlets which are sets of flat ribbons of actin filaments. The ribbons in each set are separated by approximately 650 A. Numerous whiskers 30 A in diameter extend from each ribbon's face, interconnecting adjacent ribbons. The nonrootlet filaments, except at the margins of the cell, occur primarily as single filaments. Like the ribbons, they are bristling with whiskers. The patches of striae are explained by ribbons and filaments held at a 650-A separation by the whiskers that project from them. A simple model for regions of bewhiskered filaments is a box crammed full of randomly oriented test-tube brushes. A thin slice through the box will show regions of dark lines or striae due to the wire backbones of the brushes separated from one another by the bristle length. Using the computer instead of test-tube brushes, we have been able to model quantitatively the filament distribution and pattern of striae seen in the cuticular plate of the lizard. The organization of actin filaments we have deduced from our simulations differs from that found in macrophages or in the terminal web of intestinal epithelial cells.
角质板是在耳蜗毛细胞中发现的肌动蛋白丝网络。在鳄蜥中，它由从静纤毛发出的小根以及锚定这些小根的交叉连接肌动蛋白丝组成。在薄切片中，这个网络呈现出显著的650±110埃条纹斑块。通过对图像的定量分析，条纹的奥秘可以得到解释。它们部分归因于小根，小根是肌动蛋白丝的扁平带束。每组带之间相隔约650埃。许多直径为30埃的须从每条带的表面伸出，将相邻的带相互连接。非小根丝除了在细胞边缘外，主要以单丝形式存在。与带一样，它们也布满了须。条纹斑块是由带和丝被从它们伸出的须以650埃的间距固定而形成的。有须丝区域的一个简单模型是一个装满随机取向试管刷的盒子。穿过盒子的薄片会显示出暗线或条纹区域，这是由于刷子的金属丝骨架被刷毛长度隔开。使用计算机而不是试管刷，我们能够定量模拟蜥蜴角质板中看到的丝分布和条纹图案。我们从模拟中推断出的肌动蛋白丝组织与巨噬细胞或肠上皮细胞终末网中的不同。
