Lamin B distribution and association with peripheral chromatin revealed by optical sectioning and electron microscopy tomography.
Lamin B distribution and association with peripheral chromatin revealed by optical sectioning and electron microscopy tomography.
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DOI：
10.1083/jcb.123.6.1671
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发表时间：
1993-12
期刊：
影响因子：
--
通讯作者：
Thilenius A
中科院分区：
文献类型：
--
作者：
Belmont AS;Zhai Y;Thilenius A
我们使用了免疫金染色、光学切片显微镜、中压电子显微镜以及电子显微镜断层扫描技术相结合的方法，来检测层粘连蛋白B在CHO细胞核膜上的分布。先前已发表的关于核层粘连蛋白染色的光学显微镜和电子显微镜研究之间明显的不一致之处得到了解决。在光学显微镜分辨率下，可以看到一个明显的开放纤维网络。层粘连蛋白B和核孔的共定位表明，这些间隔约0.5微米的明显纤维与核孔的表面分布呈反相关；孔簇位于层粘连蛋白B重度染色区域之间或相邻位置。在更高的电子显微镜分辨率下进行观察发现，这个明显的层粘连蛋白B网络并不对应于一个由间隔较大、离散的层粘连蛋白丝束构成的实际网络。相反，它反映了在约0.5微米尺寸范围内层粘连蛋白染色的定量变化，叠加在一个更连续但仍然复杂的层粘连蛋白丝分布上，在0.1 - 0.2微米尺寸范围内具有空间异质性。有趣的是，在这种更高分辨率下的层粘连蛋白B染色与下方的染色质分布高度相关。高浓度的层粘连蛋白B直接“覆盖”在与核膜相关的大规模染色质结构域的表面。
We have used a combination of immunogold staining, optical sectioning light microscopy, intermediate voltage electron microscopy, and EM tomography to examine the distribution of lamin B over the nuclear envelope of CHO cells. Apparent inconsistencies between previously published light and electron microscopy studies of nuclear lamin staining were resolved. At light microscopy resolution, an apparent open fibrillar network is visualized. Colocalization of lamin B and nuclear pores demonstrates that these apparent fibrils, separated by roughly 0.5 micron, are anti-correlated with the surface distribution of nuclear pores; pore clusters lie between or adjacent to regions of heavy lamin B staining. Examination at higher, EM resolution reveals that this apparent lamin B network does not correspond to an actual network of widely spaced, discrete bundles of lamin filaments. Rather it reflects a quantitative variation in lamin staining over a roughly 0.5-micron size scale, superimposed on a more continuous but still complex distribution of lamin filaments, spatially heterogeneous on a 0.1-0.2-micron size scale. Interestingly, lamin B staining at this higher resolution is highly correlated to the underlying chromatin distribution. Heavy concentrations of lamin B directly "cap" the surface of envelope associated, large-scale chromatin domains.