Lazebnik Y A, Cole S, Cooke C A, Nelson W G, Earnshaw W C
Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205.
J Cell Biol. 1993 Oct;123(1):7-22. doi: 10.1083/jcb.123.1.7.
We have developed a cell-free system that induces the morphological transformations characteristic of apoptosis in isolated nuclei. The system uses extracts prepared from mitotic chicken hepatoma cells following a sequential S phase/M phase synchronization. When nuclei are added to these extracts, the chromatin becomes highly condensed into spherical domains that ultimately extrude through the nuclear envelope, forming apoptotic bodies. The process is highly synchronous, and the structural changes are completed within 60 min. Coincident with these morphological changes, the nuclear DNA is cleaved into a nucleosomal ladder. Both processes are inhibited by Zn2+, an inhibitor of apoptosis in intact cells. Nuclear lamina disassembly accompanies these structural changes in added nuclei, and we show that lamina disassembly is a characteristic feature of apoptosis in intact cells of mouse, human and chicken. This system may provide a powerful means of dissecting the biochemical mechanisms underlying the final stages of apoptosis.
我们开发了一种无细胞系统，该系统可在分离的细胞核中诱导出凋亡特有的形态学转变。该系统使用经连续S期/M期同步化处理的有丝分裂期鸡肝癌细胞制备的提取物。当将细胞核添加到这些提取物中时，染色质会高度浓缩成球形结构域，最终通过核膜挤出，形成凋亡小体。这个过程高度同步，结构变化在60分钟内完成。与这些形态学变化同时发生的是，核DNA被切割成核小体梯状条带。这两个过程都受到Zn2+的抑制，Zn2+是完整细胞中凋亡的抑制剂。添加的细胞核中的这些结构变化伴随着核纤层的解体，并且我们表明核纤层解体是小鼠、人类和鸡的完整细胞中凋亡的一个特征。该系统可能为剖析凋亡最后阶段潜在的生化机制提供一种强有力的手段。
