Cain K, Inayat-Hussain S H, Wolfe J T, Cohen G M
MRC Toxicology Unit, University of Leicester, UK.
FEBS Lett. 1994 Aug 8;349(3):385-91. doi: 10.1016/0014-5793(94)80001-4.
Internucleosomal cleavage of DNA has often been regarded as the biochemical hallmark of apoptosis. We now demonstrate in isolated rat liver nuclei that DNA is initially cleaved into > or = 700, 200-250 kbp and 30-50 kbp fragments via a multi-step process, which is activated by Mg2+ and Mg2+(+)Ca2+ but not by Ca2+ alone. The subsequent internucleosomal cleavage requires both cations. These findings demonstrate that a key event in the apoptotic process is the fragmentation of DNA into large kbp fragments by either a Mg(2+)-dependent process (which can be potentiated by Ca2+) and/or by a Ca2+/Mg2+ activated endonuclease(s).
DNA的核小体间切割常被视为细胞凋亡的生化标志。我们现在在分离的大鼠肝细胞核中证明，DNA最初通过一个多步骤过程被切割成≥700、200 - 250 kbp和30 - 50 kbp的片段，该过程由Mg2 +和Mg2 +（+）Ca2 +激活，但单独的Ca2 +不能激活。随后的核小体间切割需要这两种阳离子。这些发现表明，细胞凋亡过程中的一个关键事件是DNA通过Mg（2 +）依赖的过程（可被Ca2 +增强）和/或Ca2 + / Mg2 +激活的核酸内切酶切割成大的kbp片段。
