The cortical endoplasmic reticulum (ER) of the mouse egg: Localization of ER clusters in relation to the generation of repetitive calcium waves
The cortical endoplasmic reticulum (ER) of the mouse egg: Localization of ER clusters in relation to the generation of repetitive calcium waves
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DOI：
10.1006/dbio.1999.9445
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发表时间：
1999-11-15
影响因子：
2.7
通讯作者：
Terasaki, M
中科院分区：
文献类型：
--
作者：
Kline, D;Mehlmann, L;Terasaki, M
成熟小鼠卵的内质网（ER）由细管状网络和皮质中明显的积累组成。使用荧光亲脂染料 DiI，在完整鸡蛋和体外皮质制剂中对 ER 进行可视化。分离皮质制剂中 ER 的免疫荧光标记表明，ER 簇含有肌醇 1,4,5-三磷酸 (IP3) 受体，表明在 IP3 触发的精子诱导的 Ca2+ 瞬变中发挥着重要作用。我们对受精期间的 ER 以及随后的 Ca2+ 瞬变进行了成像，发现这些簇在整个时期保持完整。光漂白后荧光的恢复证实 ER 簇与网状 ER 网络是连续的，并且这些结构在受精诱导的 Ca2+ 瞬变期间保持稳定和连续； IP3 注入期间也保持连续性。这些结果表明，与棘皮动物卵相反，小鼠卵在受精时释放 Ca2+ 时，内质网不会受到破坏。皮质 ER 簇的定位和表观稳定性可能对于产生 Ca2+ 振荡很重要，而 Ca2+ 振荡是哺乳动物受精卵的特征。细胞内 Ca2+ 成像显示，Ca2+ 瞬变起源于含有丰富 ER 簇的卵子半球，因此小鼠含有负责产生 Ca2+ 波的稳定皮质起搏器。 (C) 1999 年学术出版社。
The endoplasmic reticulum (ER) of the mature mouse egg consists of a fine tubular network and pronounced accumulations in the cortex. The ER was visualized both in intact eggs and with in vitro preparations of the cortex using the fluorescent lipophilic dye, DiI. Immunofluorescent labeling of the ER in isolated cortical preparations demonstrated that the ER clusters contain inositol 1,4,5-trisphosphate (IP3) receptors, indicating an important involvement in sperm-induced Ca2+ transients, which are triggered by IP3. We imaged the ER during fertilization and the subsequent Ca2+ transients and found that the clusters remained intact throughout this period. Recovery of fluorescence after photobleaching established that the ER clusters are continuous with the reticular ER network and that these structures remain stable and continuous throughout the time of fertilization-induced Ca2+ transients; continuity also remained during IP3 injection. These results indicate that, in contrast to echinoderm eggs, the ER of mouse eggs does not become disrupted when it releases Ca2+ at fertilization. The localization and apparent stability of the cortical ER clusters may be important in generating Ca2+ oscillations, which are characteristic of fertilized mammalian eggs. Imaging of intracellular Ca2+ revealed that Ca2+ transients originate in the hemisphere of the egg that contains abundant ER clusters, thus the mouse contains a stable cortical pacemaker responsible for generating Ca2+ waves. (C) 1999 Academic Press.