ON THE ATTACHMENT OF THE NUCLEAR PORE COMPLEX
ON THE ATTACHMENT OF THE NUCLEAR PORE COMPLEX
复制标题
论核孔复合体的附着
作者：
R. P. Aaronson;G. Blobel
用Triton X-100洗涤剂处理离体大鼠肝核后，电镜检查显示核膜内外膜均被完全去除。剥去包膜的细胞核在形态和内部超微结构上均未见改变。最引人注目的是，在未经处理的细胞核中，核孔复合物似乎是核膜的组成部分，它们保留在其特征位置，即通过外周异染色质的通道的远端。对经过洗涤剂处理的核的化学成分测定表明，95%以上的核磷脂被溶解，从而证实了核膜的形态缺失。此外，洗涤剂处理也溶解了约10%的核蛋白。聚丙烯酰胺凝胶电泳在SDS存在下对溶解蛋白进行分析，表明这些蛋白属于几个特定的类别，可能代表核膜的主要多肽。形态学和生化基础上核膜的完全缺失支持了核孔复合体不需要膜来附着核或维持其自身结构完整性的观点。
Electron microscope examination of isolated rat liver nuclei after treatment with the detergent Triton X-100 revealed the complete removal of both the inner and outer membranes of the nuclear envelope. The envelope-denuded nuclei did not show any change in either shape or internal ultrastructure. Most strikingly, the nuclear pore complexes, which in untreated nuclei appear to be integral components of the nuclear envelope, were retained in their characteristic location at the distal ends of the channels leading through the peripheral heterochromatin. Determination of the chemical composition of detergent-treated nuclei showed that over 95% of the nuclear phospholipid was solubilized, thus corroborating the morphological absence of nuclear membranes. Furthermore, detergent treatment also solubilized approximately 10% of the nuclear protein. Analysis of the solubilized protein by polyacrylamide gel electrophoresis in the presence of SDS indicated that these proteins belong to a few specific classes which presumably represent the major polypeptides of the nuclear membranes. The total absence of the nuclear envelope on both morphological and biochemical grounds supports the idea that the nuclear pore complex does not require the membranes either for attachment to the nucleus or for maintenance of its own structural integrity.