Giannakis C, Forbes I J, Zalewski P D
Department of Medicine, University of Adelaide, Queen Elizabeth Hospital.
Biochem Biophys Res Commun. 1991 Dec 16;181(2):915-20. doi: 10.1016/0006-291x(91)91278-k.
Ca2+/Mg(2+)-dependent endonuclease has been implicated in the extensive internucleosomal DNA fragmentation that accompanies apoptosis (gene-directed cell death). We present further evidence that this enzyme is involved in apoptosis. Ca2+/Mg2+ nuclease activity was increased about 6-fold during colchicine-induced apoptosis in human chronic lymphocytic leukaemia cells. The increase in activity coincided with onset of DNA fragmentation. Spleen, liver, kidney and thymus expressed high levels of this enzyme while lung, brain, heart and testis contained little activity. Cells from tissues with high Ca2+/Mg2+ nuclease activity underwent rapid DNA fragmentation in response to a Ca2+ flux. Physiological concentrations of Zn2+ known to inhibit both apoptosis and DNA fragmentation also inhibited Ca2+/Mg2+ nuclease activity.
钙离子/镁离子依赖性核酸内切酶与凋亡（基因导向性细胞死亡）过程中广泛的核小体间DNA片段化有关。我们提供了进一步的证据表明该酶参与凋亡过程。在秋水仙碱诱导的人慢性淋巴细胞白血病细胞凋亡过程中，钙离子/镁离子核酸酶活性增加了约6倍。活性的增加与DNA片段化的开始同时发生。脾脏、肝脏、肾脏和胸腺中该酶表达水平较高，而肺、脑、心脏和睾丸中活性较低。来自具有高钙离子/镁离子核酸酶活性组织的细胞在钙离子通量的作用下迅速发生DNA片段化。已知抑制凋亡和DNA片段化的生理浓度的锌离子也抑制钙离子/镁离子核酸酶活性。
