Saint-Jeannet J P, Dawid I B
Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
Dev Biol. 1994 Dec;166(2):755-62. doi: 10.1006/dbio.1994.1353.
A fate map of the progeny derived from all blastomeres of the 32-cell stage embryo of the leopard frog Rana pipiens has been generated. Embryos presenting regular cleavages were injected into two pairs of blastomeres with fluorescein- and Texas red-lysine dextran. By stage 21, embryos were sectioned and the tissue distribution of labeled clones was determined. The results of 93 clones were pooled to give a fate map which represents the derivation of each tissue from the different blastomeres of the 32-cell embryo. The results show that all blastomeres give rise to multiple tissues and all tissues are derived from at least two, and usually more, pairs of blastomeres. Although there is a general tendency for ectoderm to derive from the animal hemisphere, endoderm from the vegetal hemisphere, and mesoderm from the equatorial region, the boundaries between germ layers are not sharply defined at the 32-cell stage but rather appear as a series of overlapping zones. The fate map of R. pipiens is quite similar to that of Xenopus laevis but differs in some details that are discussed. As in all vertebrates, the R. pipiens fate map is not fully deterministic but nevertheless has predictive value in that tissues are populated by the progeny of the same blastomeres in different embryos.
已经构建了豹蛙（泽蛙）32细胞期胚胎所有卵裂球后代的命运图谱。将呈现规则分裂的胚胎的两对卵裂球分别注射荧光素和德克萨斯红赖氨酸葡聚糖。到第21阶段时，将胚胎切片并确定标记克隆的组织分布。汇总93个克隆的结果得到一个命运图谱，该图谱代表了32细胞胚胎不同卵裂球产生的各组织。结果表明，所有卵裂球都产生多种组织，所有组织至少源自两对，通常更多对卵裂球。尽管一般趋势是外胚层源自动物半球，内胚层源自植物半球，中胚层源自赤道区域，但在32细胞期胚层之间的边界并非清晰界定，而是呈现为一系列重叠区域。泽蛙的命运图谱与非洲爪蟾的非常相似，但在一些细节上有所不同，文中对此进行了讨论。与所有脊椎动物一样，泽蛙的命运图谱并非完全确定，但仍然具有预测价值，因为不同胚胎中相同卵裂球的后代构成了各组织。
