Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
Semin Cell Dev Biol. 2020 Nov;107:147-160. doi: 10.1016/j.semcdb.2020.07.010. Epub 2020 Aug 15.
The regionalisation of growing tissues into compartments that do not mix is thought to be a common motif of animal development. Compartments and compartmental boundaries were discovered by lineage studies in the model organism Drosophila. Since then, many compartment boundaries have been identified in developing tissues, from insects to vertebrates. These are important for animal development, because boundaries localize signalling centres that control tissue morphogenesis. Compartment boundaries are boundaries of lineage restriction, where specific mechanisms keep boundaries straight and cells segregated. Here, we review the mechanisms of cell sorting at boundaries found in early Drosophila embryos. The parasegmental boundaries, separating anterior from posterior compartments in the embryo, keep cells segregated by increasing actomyosin contractility at boundary cell-cell interfaces. Differential actomyosin contractility in turn promotes fold formation and orients cell division. Earlier in development, actomyosin differentials are also important for cell sorting during axis extension. Specific cell surface asymmetries and signalling pathways are required to initiate and maintain these actomyosin differentials.
将生长组织分区为不混合的隔室被认为是动物发育的一个共同特征。隔室和隔室边界是通过模式生物果蝇的谱系研究发现的。自那时以来，许多发育组织中的隔室边界已经被确定，从昆虫到脊椎动物。这些对于动物发育很重要，因为边界定位了控制组织形态发生的信号中心。隔室边界是谱系限制的边界，其中特定的机制保持边界笔直和细胞分离。在这里，我们回顾了在早期果蝇胚胎中发现的边界处细胞分选的机制。体节边界将胚胎中的前区和后区分开，通过增加边界细胞-细胞界面处的肌动球蛋白收缩力来保持细胞分离。肌动球蛋白的差异收缩反过来又促进了褶皱的形成和细胞分裂的定向。在发育早期，肌动球蛋白的差异对于轴延伸过程中的细胞分选也很重要。需要特定的细胞表面不对称性和信号通路来启动和维持这些肌动球蛋白的差异。
