Rivera-Bennetts Alma Karina, Elinson Richard P
Department of Zoology, University of Toronto, Toronto, Ontario M5S 1A1, Canada.
Dev Growth Differ. 1995 Dec;37(6):631-639. doi: 10.1046/j.1440-169X.1995.t01-5-00002.x.
The early development of several species involves the segregation of cytoplasmic components into different regions of the egg. In Xenopus zygotes, a 30° rotation displaces the central animal cytoplasm to the future dorsal side of the embryo. To elucidate the role of the central animal cytoplasm in dorsal determination, we induced germinal vesicle breakdown (GVBD) closer to the equator by cold/centrifugation treatment of oocytes. Centrifugation moved the germinal vesicle to the centripetal side; eggs with such displaced GVBD fertilized and began to develop normally. Dorsal embryonic structures tended to develop on the GVBD side of the egg, but displacement of the GVBD was insufficient to rescue dorsal structures in axis-deficient embryos. The labeling of yolk platelets of oocytes with Trypan Blue revealed similar cytoplasmic patterns in control and treated eggs. Furthermore, 67% of treated eggs had Danilchik's swirl, indicative of the dorsal side, on the GVBD side. In conclusion, both the swirl and dorsal development tend to occur on the GVBD side of cold/centrifuged eggs; however, displaced GVBD cannot by itself determine dorsality.
几种物种的早期发育涉及细胞质成分在卵子不同区域的分离。在非洲爪蟾受精卵中，30°的旋转将中央动物极细胞质转移到胚胎未来的背侧。为了阐明中央动物极细胞质在背侧决定中的作用，我们通过对卵母细胞进行冷处理/离心处理，在更靠近赤道的位置诱导生发泡破裂（GVBD）。离心将生发泡移向向心侧；具有这种移位GVBD的卵子受精并开始正常发育。胚胎的背侧结构倾向于在卵子的GVBD侧发育，但GVBD的移位不足以挽救轴缺陷胚胎中的背侧结构。用台盼蓝对卵母细胞的卵黄小板进行标记，结果显示对照卵和处理过的卵具有相似的细胞质模式。此外，67%的处理过的卵子在GVBD侧有达尼尔奇克氏漩涡，这表明是背侧。总之，漩涡和背侧发育都倾向于发生在冷处理/离心处理过的卵子的GVBD侧；然而，移位的GVBD本身并不能决定背侧性。
