Bauer D V, Huang S, Moody S A
Department of Anatomy and Cell Biology, University of Virginia.
Development. 1994 May;120(5):1179-89. doi: 10.1242/dev.120.5.1179.
Recent investigations into the roles of early regulatory genes, especially those resulting from mesoderm induction or first expressed in the gastrula, reveal a need to elucidate the developmental history of the cells in which their transcripts are expressed. Although fates both of the early blastomeres and of regions of the gastrula have been mapped, the relationship between the two sets of fate maps is not clear and the clonal origin of the regions of the stage 10 embryo are not known. We mapped the positions of each blastomere clone during several late blastula and early gastrula stages to show where and when these clones move. We found that the dorsal animal clone (A1) begins to move away from the animal pole at stage 8, and the dorsal animal marginal clone (B1) leaves the animal cap by stage 9. The ventral animal clones (A4 and B4) spread into the dorsal animal cap region as the dorsal clones recede. At stage 10, the ventral animal clones extend across the entire dorsal animal cap. These changes in the blastomere constituents of the animal cap during epiboly may contribute to the changing capacity of the cap to respond to inductive growth factors. Pregastrulation movements of clones also result in the B1 clone occupying the vegetal marginal zone to become the primary progenitor of the dorsal lip of the blastopore (Spemann's Organizer). This report provides the fundamental descriptions of clone locations during the important periods of axis formation, mesoderm induction and neural induction. These will be useful for the correct targeting of genetic manipulations of early regulatory events.
最近对早期调控基因作用的研究，特别是那些由中胚层诱导产生或最早在原肠胚中表达的基因，揭示了阐明其转录本所表达细胞的发育历史的必要性。尽管早期卵裂球和原肠胚区域的命运已经被绘制出来，但这两组命运图谱之间的关系尚不清楚，而且10期胚胎区域的克隆起源也未知。我们绘制了几个晚期囊胚和早期原肠胚阶段每个卵裂球克隆的位置，以显示这些克隆在何处以及何时移动。我们发现，背侧动物克隆（A1）在8期开始从动物极移开，背侧动物边缘克隆（B1）在9期离开动物帽。随着背侧克隆后退，腹侧动物克隆（A4和B4）扩散到背侧动物帽区域。在10期，腹侧动物克隆延伸穿过整个背侧动物帽。外包过程中动物帽卵裂球成分的这些变化可能有助于帽对诱导生长因子反应能力的改变。克隆的原肠胚形成前运动还导致B1克隆占据植物性边缘区，成为胚孔背唇（施佩曼组织者）的主要祖细胞。本报告提供了在轴形成、中胚层诱导和神经诱导的重要时期克隆位置的基本描述。这些将有助于对早期调控事件进行正确的基因操作靶向。
