Do embryonic polar bodies commit suicide?
Do embryonic polar bodies commit suicide?
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DOI：
10.1017/s0967199412000159
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发表时间：
2014-02-01
期刊：
影响因子：
1.7
通讯作者：
Koppel, Juraj
中科院分区：
文献类型：
--
作者：
Fabian, Dusan;Cikos, Stefan;Koppel, Juraj
排泄和消除不必要的配子/胚胎物质是决定所有生物进一步发育成功的关键事件之一。卵母细胞在排卵前产生第一个极体以完成成熟过程，并在受精后立即释放第二个极体。这项研究的目的是汇编小鼠早期植入前发育过程中极体消除的生理学概述。我们的结果表明，即使在合子阶段，四分之三的第一极体也消失了；4-细胞期胚胎只有一个(第二)极体，第二极体的消除在发育后期持续进行。第一和第二极体都表现出几个典型的凋亡特征：磷脂酰丝氨酸重新分布(首次在第一极体中观察到)，特定的DNA降解，浓缩的核形态，以及在凋亡过程的末期不能从细胞核中排除阳离子染料。Caspase-3活性仅在第二极体记录到。从形态上看，小鼠极体的行为与受损的胚胎细胞非常相似，后者与邻近的卵裂球失去了联系。总而言之，极体拥有触发和执行主动自杀过程所需的所有分子设备。此外，与濒临死亡的胚胎细胞类似，应激的外部条件(体外培养)可能会加速和增加胚胎中极体的凋亡消除。
The extrusion and elimination of unnecessary gametic/embryonic material is one of the key events that determines the success of further development in all living organisms. Oocytes produce the first polar body to fulfill the maturation process just before ovulation, and release the second polar body immediately after fertilization. The aim of this study was to compile a physiological overview of elimination of polar bodies during early preimplantation development in mice. Our results show that three-quarters of the first polar bodies were lost even at the zygotic stage; the 4-cell stage embryos contained only one (second) polar body, and the elimination of second polar bodies proceeded continuously during later development. Both first and second polar bodies showed several typical features of apoptosis: phosphatidylserine redistribution (observed for the first time in the first polar body), specific DNA degradation, condensed nuclear morphology, and inability to exclude cationic dye from the nucleus during the terminal stage of the apoptotic process. Caspase-3 activity was recorded only in the second polar body. From the morphological point of view, mouse polar bodies acted very similarly to damaged embryonic cells which have lost contact with their neighboring blastomeres. In conclusion, polar bodies possess all the molecular equipment necessary for triggering and executing an active suicide process. Furthermore, similarly as in dying embryonic cells, stressing external conditions (culture in vitro) might accelerate and increase the incidence of apoptotic elimination of the polar bodies in embryos.