Laboratory for Histogenetic Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai, 980-8578, Japan.
Research Institute for Electronic Science, Hokkaido University, Sapporo, 001-0020, Japan.
Nat Commun. 2020 Dec 10;11(1):6320. doi: 10.1038/s41467-020-20118-y.
Maintaining lineage restriction boundaries in proliferating tissues is vital to animal development. A long-standing thermodynamics theory, the differential adhesion hypothesis, attributes cell sorting phenomena to differentially expressed adhesion molecules. However, the contribution of the differential adhesion system during tissue morphogenesis has been unsubstantiated despite substantial theoretical support. Here, we report that Toll-1, a transmembrane receptor protein, acts as a differentially expressed adhesion molecule that straightens the fluctuating anteroposterior compartment boundary in the abdominal epidermal epithelium of the Drosophila pupa. Toll-1 is expressed across the entire posterior compartment under the control of the selector gene engrailed and displays a sharp expression boundary that coincides with the compartment boundary. Toll-1 corrects local distortions of the boundary in the absence of cable-like Myosin II enrichment along the boundary. The reinforced adhesion of homotypic cell contacts, together with pulsed cell contraction, achieves a biased vertex sliding action by resisting the separation of homotypic cell contacts in boundary cells. This work reveals a self-organizing system that integrates a differential adhesion system with pulsed contraction of cells to maintain lineage restriction boundaries.
维持增殖组织中的谱系限制边界对于动物发育至关重要。一个长期存在的热力学理论，即差异粘附假说，将细胞分选现象归因于差异表达的粘附分子。然而，尽管有大量的理论支持，但差异粘附系统在组织形态发生过程中的贡献尚未得到证实。在这里，我们报告 Toll-1，一种跨膜受体蛋白，作为一个差异表达的粘附分子，在果蝇蛹的腹部表皮上皮中使波动的前后隔边界变直。Toll-1 在整个后隔中表达，受选择基因 engrailed 的控制，并显示出与隔边界一致的锐利表达边界。在没有沿边界富集的线状肌球蛋白 II 的情况下，Toll-1 纠正了边界的局部扭曲。同质细胞接触的增强粘附，加上脉冲细胞收缩，通过抵抗边界细胞中同质细胞接触的分离，实现了偏向顶点滑动作用。这项工作揭示了一个自组织系统，它将差异粘附系统与细胞的脉冲收缩结合起来，以维持谱系限制边界。
