A new look at kinetochore structure in vertebrate somatic cells using high-pressure freezing and freeze substitution
A new look at kinetochore structure in vertebrate somatic cells using high-pressure freezing and freeze substitution
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DOI：
10.1007/s004120050320
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发表时间：
1998-12-01
期刊：
影响因子：
1.6
通讯作者：
Rieder, CL
中科院分区：
文献类型：
--
作者：
McEwen, BF;Hsieh, CE;Rieder, CL
三十年的结构分析形成了这样一种观点：脊椎动物细胞中的动粒是一种盘状结构，由三个不同的结构域组成。其中最显著的是一个明显的电子不透明的外板，它由一个染色浅的电子透明的中板与一个与着丝粒周边异染色质表面相关的内板隔开。纺锤体微管终止于外板，在没有微管时，一层明显的细丝冠状物从该板的细胞质表面辐射出来。在此，我们首次报道了在未经处理以及用秋水仙酰胺处理的脊椎动物体细胞（PtK1）中动粒的超微结构，这些细胞是通过高压冷冻和冷冻替代法进行制备以实现最佳结构保存的。在连续薄切片和电子断层扫描重建中，动粒呈现为一层50 - 75纳米厚的染色浅的纤维材料垫，它与着丝粒异染色质的电子更不透明的表面直接相连。这个垫相当于常规制备中的外板，并且在其细胞质表面被一个明显的100 - 150纳米宽的区域环绕，该区域排除了核糖体和其他细胞质成分。这个区域的高倍放大图显示它包含一个染色浅的薄的松散网络（
Three decades of structural analysis have produced the view that the kinetochore in vertebrate cells is a disk-shaped structure composed of three distinct structural domains. The most prominent of these consists of a conspicuous electron opaque outer plate that is separated by a light-staining electron-translucent middle plate from an inner plate associated with the surface of the pericentric heterochromatin. Spindle microtubules terminate in the outer plate and, in their absence, a conspicuous corona of fine filaments radiates from the cytoplasmic surface of this plate. Here we report for the first time the ultrastructure of kinetochores in untreated and Colcemid-treated vertebrate somatic (PtK1) cells prepared for optimal structural preservation using high-pressure freezing and freeze substitution. In serial thin sections, and electron tomographic reconstructions, the kinetochore appears as a 50-75 nm thick mat of light-staining fibrous material that is directly connected with the more electron-opaque surface of the centromeric heterochromatin. This mat corresponds to the outer plate in conventional preparations, and is surrounded on its cytoplasmic surface by a conspicuous 100-150 nm wide zone that excludes ribosomes and other cytoplasmic components. High magnification views of this zone reveal that it contains a loose network of light-staining, thin (