Eisen A, Reynolds G T
J Cell Biol. 1985 May;100(5):1522-7. doi: 10.1083/jcb.100.5.1522.
The source and sinks for the intracellular calcium released during fertilization were examined in single eggs from the sea urchin, Arbacia punctulata. Single eggs were microinjected with the calcium photoprotein, aequorin. The calcium-aequorin luminescence was measured with a microscope-photomultiplier or observed with a microscope-image intensifier-video system. In the normal egg a propagated release has been observed. The source of the calcium was investigated in the organelle-stratified centrifuged egg and by the use of mitochondrial uncouplers. In the organelle-stratified centrifuged egg, the calcium-aequorin luminescence was found to originate from the clear zone. The principal constituent of the clear zone is the endoplasmic reticulum. Other potential sources of calcium are the mitochondria. Their contribution to the calcium transient was investigated by exposure of aequorin-injected eggs to mitochondrial uncouplers either before or after fertilization. There was no calcium released from the mitochondria before fertilization. A very large calcium store was released from the mitochondria after fertilization. Interestingly, eggs fertilized in the presence of uncouplers showed no increase in the calcium-aequorin luminescence over untreated eggs. Apparently, in the absence of mitochondrial uptake, other sinks for calcium with affinity and capacity similar to the mitochondria exist, but their nature is unknown. We suggest that the endoplasmic reticulum is the source of the intracellular calcium released upon fertilization and that the mitochondria are the principal sink. The results are discussed with regard to the metabolic activation of the egg.
对海胆（刺冠海胆）单个卵细胞受精过程中释放的细胞内钙的来源和汇进行了研究。向单个卵细胞中显微注射钙光蛋白水母发光蛋白。用显微镜 - 光电倍增管测量钙 - 水母发光蛋白的发光，或用显微镜 - 图像增强器 - 视频系统进行观察。在正常卵细胞中观察到了一种传播性释放。通过对细胞器分层离心的卵细胞以及使用线粒体解偶联剂来研究钙的来源。在细胞器分层离心的卵细胞中，发现钙 - 水母发光蛋白的发光源自透明区。透明区的主要成分是内质网。钙的其他潜在来源是线粒体。通过在受精前或受精后将注射了水母发光蛋白的卵细胞暴露于线粒体解偶联剂来研究它们对钙瞬变的贡献。受精前线粒体没有释放钙。受精后线粒体释放了大量的钙储存。有趣的是，在存在解偶联剂的情况下受精的卵细胞，其钙 - 水母发光蛋白的发光相对于未处理的卵细胞没有增加。显然，在没有线粒体摄取的情况下，存在其他对钙具有与线粒体相似亲和力和容量的钙汇，但它们的性质尚不清楚。我们认为内质网是受精时释放的细胞内钙的来源，而线粒体是主要的钙汇。结合卵细胞的代谢激活对结果进行了讨论。
