Ca2+ oscillations stimulate an ATP increase during fertilization of mouse eggs
Ca2+ oscillations stimulate an ATP increase during fertilization of mouse eggs
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DOI：
10.1016/j.ydbio.2006.06.032
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发表时间：
2006-10-01
影响因子：
2.7
通讯作者：
Swann, Karl
中科院分区：
文献类型：
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作者：
Campbell, Karen;Swann, Karl
哺乳动物的卵子和胚胎依靠线粒体三磷酸腺苷的生产生存和进行着床前的发育。已有研究表明，受精时的钙离子振荡会导致线粒体NAD+和黄素蛋白的减少，这表明它们也可能导致细胞质ATP水平的变化。在这里，我们通过成像钙染料的荧光和萤火虫荧光素酶的发光来监测受精卵中细胞内钙和三磷酸腺苷的水平。在受精时，ATP水平首次升高，第一次是钙离子瞬变，第二次是在大约1小时后。胞质中的ATP浓度从受精前的1.9 mM增加到峰值3 mM。随着钙离子振荡的终止，ATP水平恢复到受精前的水平。当其他刺激物增加Ca~(2+)时，也可引起ATP的升高，当注射BAPTA抑制Ca~(2+)振荡时，ATP的升高被阻断。此外，当鸡蛋被环己亚胺激活时，ATP没有增加，这不会引起钙离子的增加。这些数据表明，哺乳动物受精与胞浆ATP的突然而短暂的增加有关，而钙振荡是导致这种ATP水平增加的必要条件和充分条件。(C)2006 Elsevier Inc.保留所有权利。
Mammalian eggs and embryos rely upon mitochondrial ATP production to survive and proceed through preimplantation development. Ca2+ oscillations at fertilization have been shown to cause a reduction of mitochondrial NAD+ and flavoproteins, suggesting they might also cause changes in cytosolic ATP levels. Here, we have monitored intracellular Ca2+ and ATP levels in fertilizing mouse eggs by imaging the fluorescence of a Ca2+ dye and luminescence of firefly luciferase. At fertilization an initial increase in ATP levels occurs with the first Ca2+ transient, with a second increase occurring about 1 h later. The increase in cytosolic ATP was estimated to be from a prefertilization concentration of 1.9 mM to a peak value of 3 mM. ATP levels returned to prefertilization values as the Ca2+ oscillations terminated. An increase in ATP also occurred with other stimuli that increase Ca2+ and it was blocked when Ca2+ oscillations were inhibited by BAPTA injection. Additionally, an ATP increase was not seen when eggs were activated by cycloheximide, which does not cause a Ca2+ increase. These data suggest that mammalian fertilization is associated with a sudden but transient increase in cytosolic ATP and that Ca2+ oscillations are both necessary and sufficient to cause this increase in ATP levels. (c) 2006 Elsevier Inc. All rights reserved.