Kominami T
Department of Biology, Faculty of Science, Ehime University, Matsuyama, Japan.
Dev Biol. 1988 May;127(1):187-96. doi: 10.1016/0012-1606(88)90200-x.
To elucidate a relationship between early cleavage planes and dorso-ventral (DV)-axis of sea urchin embryos, a fluorescent dye, Lucifer Yellow CH, was iontophoretically introduced into one blastomere at the 2-cell stage, and the location of the progeny cells was determined in the half-labeled prism larvae by examining the embryos from the animal pole. The boundary plane which divides the embryonic tissue into the labeled and nonlabeled parts was (1) coincident with, (2) perpendicular to, or (3) obliquely crossing the larval plane of bilateral symmetry. The oblique boundaries took only two angles mutually symmetrical with regard to the DV-axis of embryos. Combining these labeling patterns, the tissue of prism larvae could be divided into 8 sectors around the animal-vegetal axis. When the 2-cell stage embryos with different diameters of sister blastomeres were labeled with the dye, one end of the boundary plane was again found at one of the 8 boundary points noticed in equally cleaved embryos, while the other was observed to fall in the middle of a sector. These results indicate that the DV-axis of the embryo is established according to the spatial arrangement of blastomeres during the 5-6th cleavage stages when blastomeres align in 8 rows in meridional direction. It was also suggested that intercellular communication takes part in the determination of the fate of individual founder blastomeres during the two subsequent cleavages, i.e., 7-8th cleavage stages.
为阐明海胆胚胎早期分裂面与背腹（DV）轴之间的关系，在二细胞期通过离子电渗法将荧光染料路西法黄CH引入一个卵裂球，并通过从动物极观察胚胎来确定半标记棱柱幼虫中后代细胞的位置。将胚胎组织分为标记部分和未标记部分的边界平面有以下三种情况：（1）与幼虫两侧对称平面重合；（2）与之垂直；（3）与之斜交。倾斜边界相对于胚胎的DV轴仅呈现两个相互对称的角度。综合这些标记模式，棱柱幼虫的组织可围绕动植物轴分为8个扇区。当用染料标记具有不同直径姐妹卵裂球的二细胞期胚胎时，边界平面的一端再次出现在均等分裂胚胎中所发现的8个边界点之一处，而另一端则落在一个扇区的中间。这些结果表明，当卵裂球在子午方向排成8排时，胚胎的DV轴是在第5 - 6次卵裂阶段根据卵裂球的空间排列建立的。研究还表明，细胞间通讯在随后的两次卵裂，即第7 - 8次卵裂阶段参与了单个奠基卵裂球命运的决定。
