Armstrong J B, Graveson A C
Department of Biology, University of Ottawa, Canada.
Dev Biol. 1988 Mar;126(1):1-6. doi: 10.1016/0012-1606(88)90232-1.
Beginning at mid-neurulation, a wave of somite segmentation passes down the axolotl body axis in a cephalocaudal direction. At 20 degrees C a somite forms every 2.57 hr. Fate-mapping of the presomitic mesoderm indicates that the primordia for the next few somites occupy nearly the same space that they will after segmentation, but that the remaining somites are densely packed in tip of the tail bud. Brief heat shocks at 37 and 38.5 degrees C reveal that within the first of these two zones, there is a graded sensitivity to the shock, with the primordia closest to the last-formed somite showing the greatest resistance. However, primordia within the densely packed tip (the packing zone) also appear resistant, or have sufficient time to repair the damage. We propose that once cells have left the packing zone, they undergo progressive patterning which renders them increasingly insensitive to the disruptive effects of heat shock, and culminates in rosette formation.
从中神经胚形成期开始，一波体节分割以头向尾的方向沿着蝾螈身体轴向下传递。在20摄氏度时，每2.57小时形成一个体节。对前体节中胚层的命运图谱分析表明，接下来几个体节的原基在分割后占据的空间与分割前几乎相同，但其余体节密集地排列在尾芽尖端。在37摄氏度和38.5摄氏度下进行短暂热休克实验发现，在这两个区域中的第一个区域内，对热休克存在梯度敏感性，最接近最后形成体节的原基表现出最大的抗性。然而，密集排列的尖端（堆积区）内的原基也表现出抗性，或者有足够的时间修复损伤。我们提出，一旦细胞离开堆积区，它们就会经历渐进性模式形成，这使得它们对热休克的破坏作用越来越不敏感，并最终形成玫瑰花结。
