Kikuyama Munehiro, Hiramoto Yukio
Biological Laboratory, The University of the Air, 2-11 Wakaba, Chiba-shi, Chiba 260, Japan.
Dev Growth Differ. 1991 Dec;33(6):633-638. doi: 10.1111/j.1440-169X.1991.00633.x.
A transient increase in intracellular Ca upon maturation in starfish oocyte was revealed by light emission of aequorin microinjected into the cell. One minute application of 1-methyladenine (1-MeAde) to a limited area of the oocyte surface was sufficient to induce the Ca transient over the entire cell though it did not induce the germinal vesicle breakdown (GVBD). Ten minutes application of 1-MeAde induced a similar Ca transient followed by GVBD. Even when the transient increase of Ca was inhibited by injecting EGTA into the oocyte, 1-MeAde treatment for a long period induced GVBD. These facts indicate that the Ca increase is neither necessary nor sufficient for maturation of the starfish oocyte. When the oocyte, which had been treated with 1-MeAde for 1 min at a limited area around the animal pole, was treated again with 1-MeAde for 10 min starting about 15 min after the first treatment, a Ca transient similar to the first one was induced and was followed by GVBD. By contrast, in the oocyte treated with 1-MeAde at an area around the vegetal pole, neither Ca transient nor GVBD was induced by the second treatment with 1-MeAde. These results indicate a difference in responsiveness to the hormone between the animal hemisphere and the vegetal hemisphere of the oocyte.
通过向海星卵母细胞显微注射水母发光蛋白的光发射，揭示了其成熟过程中细胞内钙离子的短暂增加。向卵母细胞表面的有限区域施加1分钟的1 - 甲基腺嘌呤（1 - MeAde）足以在整个细胞中诱导钙离子瞬变，尽管它不会诱导生发泡破裂（GVBD）。施加10分钟的1 - MeAde会诱导类似的钙离子瞬变，随后是GVBD。即使通过向卵母细胞注射EGTA抑制钙离子的短暂增加，长时间的1 - MeAde处理仍会诱导GVBD。这些事实表明，钙离子增加对于海星卵母细胞的成熟既不是必需的也不是充分的。当在动物极周围的有限区域用1 - MeAde处理1分钟的卵母细胞，在第一次处理后约15分钟开始再次用1 - MeAde处理10分钟时，会诱导出与第一次相似的钙离子瞬变，随后是GVBD。相比之下，在用1 - MeAde处理植物极周围区域的卵母细胞中，第二次用1 - MeAde处理既不会诱导钙离子瞬变也不会诱导GVBD。这些结果表明卵母细胞的动物半球和植物半球对该激素的反应性存在差异。
