Stern C D, Fraser S E, Keynes R J, Primmett D R
Department of Human Anatomy, Oxford, UK.
Development. 1988;104 Suppl:231-44. doi: 10.1242/dev.104.Supplement.231.
We have studied the lineage history of the progenitors of the somite mesoderm and of the neural tube in the chick embryo by injecting single cells with the fluorescent tracer, rhodamine-lysine-dextran. We find that, although single cells within the segmental plate give rise to discrete clones in the somites to which they contribute, neither the somites nor their component parts (sclerotome, dermatome, myotome or their rostral and caudal halves) are 'compartments' in the sense defined in insects. Cells in the rostral two thirds or so of the segmental plate contribute only to somite tissue and divide about every 10 h, while those in the caudal portions of this structure contribute both to the somites and to intermediate and lateral plate mesoderm derivatives. In the neural tube, the descendants of individual prospective ventral horn cells remain together within the horn, with a cycle time of 10 h. We have also investigated the role of the cell division cycle in the formation and subsequent development of somites. A single treatment of 2-day chick embryos with heat shock or a variety of drugs that affect the cell cycle all produce repeated anomalies in the pattern of somites and vertebrae that develop subsequent to the treatment. The interval between anomalies is 6-7 somites (or a multiple of this distance), which corresponds to 10 h. This interval is identical to that measured for the cell division cycle. Given that cell division synchrony is seen in the presomitic mesoderm, we suggest that the cell division cycle plays a role in somite formation. Finally, we consider the mechanisms responsible for regionalization of derivatives of the somite, and conclude that it is likely that both cell interactions and cell lineage history are important in the determination of cell fates.
我们通过向单个细胞注射荧光示踪剂罗丹明 - 赖氨酸 - 葡聚糖，研究了鸡胚中体节中胚层和神经管祖细胞的谱系历史。我们发现，尽管节段板内的单个细胞在它们所贡献的体节中产生离散的克隆，但无论是体节还是其组成部分（生骨节、皮节、肌节或它们的头侧和尾侧半部）都不是昆虫中所定义的那种“区室”。节段板头侧大约三分之二的细胞仅对体节组织有贡献，大约每10小时分裂一次，而该结构尾侧部分的细胞既对体节有贡献，也对中间和侧板中胚层衍生物有贡献。在神经管中，单个预期腹角细胞的后代保持在腹角内，细胞周期为10小时。我们还研究了细胞分裂周期在体节形成及随后发育中的作用。对2日龄鸡胚进行单次热休克处理或使用多种影响细胞周期的药物处理，都会在处理后发育的体节和椎骨模式中产生重复的异常。异常之间的间隔是6 - 7个体节（或这个距离的倍数），相当于10小时。这个间隔与测量的细胞分裂周期相同。鉴于在体节形成前的中胚层中观察到细胞分裂同步，我们认为细胞分裂周期在体节形成中起作用。最后，我们考虑了负责体节衍生物区域化的机制，并得出结论，细胞间相互作用和细胞谱系历史在细胞命运的决定中可能都很重要。
