Centre for Organismal Studies Heidelberg, Heidelberg, Germany.
European Molecular Biology Laboratory, Heidelberg, Germany.
Elife. 2018 Oct 30;7:e34616. doi: 10.7554/eLife.34616.
Extraembryonic tissues contribute to animal development, which often entails spreading over embryo or yolk. Apart from changes in cell shape, the requirements for this tissue spreading are not well understood. Here, we analyze spreading of the extraembryonic serosa in the scuttle fly . The serosa forms from a columnar blastoderm anlage, becomes a squamous epithelium, and eventually spreads over the embryo proper. We describe the dynamics of this process in long-term, whole-embryo time-lapse recordings, demonstrating that free serosa spreading is preceded by a prolonged pause in tissue expansion. Closer examination of this pause reveals mechanical coupling to the underlying yolk sac, which is later released. We find mechanical coupling prolonged and serosa spreading impaired after knockdown of . We conclude that tissue-tissue interactions provide a critical functional element to constrain spreading epithelia.
胚胎外组织有助于动物的发育，这通常需要胚胎或蛋黄的扩散。除了细胞形状的变化外，这种组织扩散的要求还不是很清楚。在这里，我们分析了裂翅蝇胚胎外浆膜的扩散。浆膜由柱状胚盘原基形成，变成鳞状上皮，最终覆盖在胚胎上。我们在长期的、整个胚胎延时记录中描述了这个过程的动态，证明游离浆膜的扩散是在组织扩张的长时间停顿之前发生的。对这个停顿的进一步观察揭示了与下面的卵黄囊的机械耦合，随后卵黄囊被释放。我们发现，在 基因敲低后，组织-组织之间的相互作用被延长，浆膜的扩散受到损害。我们的结论是，组织-组织相互作用提供了一个关键的功能元件，以限制扩散的上皮细胞。
