Danilchik M V, Denegre J M
Department of Biology, Wesleyan University, Middletown, Connecticut 06459.
Development. 1991 Apr;111(4):845-56. doi: 10.1242/dev.111.4.845.
The egg of the frog Xenopus is cylindrically symmetrical about its animal-vegetal axis before fertilization. Midway through the first cell cycle, the yolky subcortical cytoplasm rotates 30 degrees relative to the cortex and plasma membrane, usually toward the side of the sperm entry point. Dorsal embryonic structures always develop on the side away from which the cytoplasm moves. Details of the deep cytoplasmic movements associated with the cortical rotation were studied in eggs vitally stained during oogenesis with a yolk platelet-specific fluorescent dye. During the first cell cycle, eggs labelled in this way develop a complicated swirl of cytoplasm in the animal hemisphere. This pattern is most prominent on the side away from which the vegetal yolk moves, and thus correlates in position with the prospective dorsal side of the embryo. Although the pattern is initially most evident near the egg's equator or marginal zone, extensive rearrangements associated with cleavage furrowing (cytoplasmic ingression) relocate portions of the swirl to vegetal blastomeres on the prospective dorsal side.
非洲爪蟾的卵在受精前围绕其动物-植物轴呈圆柱对称。在第一个细胞周期进行到一半时，富含卵黄的皮质下细胞质相对于皮质和质膜旋转30度，通常朝着精子进入点的一侧旋转。胚胎的背侧结构总是在细胞质移动方向的相反一侧发育。利用一种卵黄小板特异性荧光染料，在卵子发生过程中对卵子进行活体染色，研究了与皮质旋转相关的深层细胞质运动的细节。在第一个细胞周期中，以这种方式标记的卵子在动物半球形成了复杂的细胞质漩涡。这种模式在植物性卵黄移动方向的相反一侧最为明显，因此在位置上与胚胎的预期背侧相关。尽管这种模式最初在卵的赤道或边缘区域附近最为明显，但与卵裂沟（细胞质内陷）相关的广泛重排将漩涡的部分区域重新定位到预期背侧的植物性卵裂球上。
