Early embryogenesis of the nematode progresses in an autonomous fashion within a protective chitin eggshell. Cell-division timing and the subsequent mechanically guided positioning of cells is virtually invariant between individuals, especially before gastrulation. Here, we have challenged this stereotypical developmental program in early stages by mechanically perturbing the embryo without breaking its eggshell. Compressing embryos to about two-thirds of their unperturbed diameter only resulted in markedly slower cell divisions. In contrast, compressing embryos to half of their native diameter frequently resulted in a loss of cytokinesis, yielding a non-natural syncytium that still allowed for multiple divisions of nuclei. Although the orientation of mitotic axes was strongly altered in the syncytium, key features of division timing and spatial arrangement of nuclei remained surprisingly similar to those of unperturbed embryos in the first few division cycles. This suggests that few, very robust mechanisms provide a basic and resilient program for safeguarding the early embryogenesis of . .

中文翻译：

---

机械干扰的线虫胚胎中有丝分裂事件的稳健时空组织

线虫的早期胚胎发生在保护性几丁质蛋壳内以自主方式进行。细胞分裂时间和随后机械引导的细胞定位在个体之间实际上是不变的，尤其是在原肠胚形成之前。在这里，我们通过在不打破蛋壳的情况下机械扰动胚胎来挑战这种早期阶段的刻板发育程序。将胚胎压缩至其未受干扰直径的约三分之二只会导致细胞分裂明显减慢。相比之下，将胚胎压缩至其天然直径的一半通常会导致胞质分裂的丧失，产生仍允许细胞核多次分裂的非天然合胞体。尽管合胞体中有丝分裂轴的方向发生了强烈改变，但在前几个分裂周期中，分裂时间和细胞核空间排列的关键特征仍然与未受干扰的胚胎惊人地相似。这表明很少有非常强大的机制可以提供基本且有弹性的程序来保护早期胚胎发生。 。