Cui Z, Houweling M, Chen M H, Record M, Chap H, Vance D E, Tercé F
Lipid and Lipoprotein Research Group, Surgical-Medical Research Institute, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
J Biol Chem. 1996 Jun 21;271(25):14668-71. doi: 10.1074/jbc.271.25.14668.
We have investigated the cell death of a Chinese hamster ovary mutant (MT-58) with a thermo-sensitive CTP:phosphocholine cytidylyltransferase, the rate-limiting enzyme of the CDP-choline pathway for phosphatidylcholine biosynthesis (Esko, J. D., Wermuth, M. M., and Raetz, C. R. H. (1981) J. Biol. Chem. 256, 7388-7393). After MT-58 cells were shifted to the restrictive temperature of 40 degrees C, the cytidylyltransferase was inactivated immediately leading to a decrease in phosphatidylcholine biosynthesis and cell death. DNA content and number of cells in the S phase decreased significantly in the dying MT-58 cells according to flow cytometrical analyses. The fragmentation of genomic DNA was detected by DNA ladders in agarose gel and release of the prelabeled genomic DNA into cytosolic fractions 14 h after the temperature shift. The dying cells underwent a dramatic reduction of cellular volume while maintaining the membrane containment of cellular contents. These events indicated that the inactivation of cytidylyltransferase triggered apoptosis in Chinese hamster ovary cells. This is the first report that apoptosis was induced in cultured cells, not by an added agent, but by a mutation in phospholipid biosynthesis.
我们研究了中国仓鼠卵巢细胞突变体（MT - 58）的细胞死亡情况，该突变体具有一种对温度敏感的CTP：磷酸胆碱胞苷转移酶，它是磷脂酰胆碱生物合成的CDP - 胆碱途径的限速酶（埃斯科，J. D.，韦尔穆特，M. M.，和雷茨，C. R. H.（1981年）《生物化学杂志》256卷，7388 - 7393页）。将MT - 58细胞转移至40摄氏度的限制温度后，胞苷转移酶立即失活，导致磷脂酰胆碱生物合成减少以及细胞死亡。根据流式细胞仪分析，在濒死的MT - 58细胞中，DNA含量和处于S期的细胞数量显著减少。温度转移14小时后，在琼脂糖凝胶中通过DNA梯带检测到基因组DNA的片段化，并且预标记的基因组DNA释放到胞质组分中。濒死细胞的细胞体积显著减小，同时维持细胞内容物的膜包裹状态。这些事件表明胞苷转移酶的失活触发了中国仓鼠卵巢细胞的凋亡。这是第一份关于在培养细胞中，凋亡不是由添加物诱导，而是由磷脂生物合成中的突变诱导的报告。
