Cellular Dynamics of Epithelial Branching Morphogenesis

我们用非细胞渗透性荧光示踪剂培养小鼠下颌下腺(SMG)，并用共聚焦时移显微镜观察上皮分支形态发生过程中的细胞行为。我们追踪单个细胞的运动，就像皮影电影一样。个别上皮细胞动态但不规律地迁移。上皮裂隙通过摆动延伸，并在分枝过程中将一簇细胞分成两个芽。我们观察了层粘连蛋白多肽A5G77f处理的SMG裂隙的超微结构，A5G77f诱导了上皮裂隙。在裂隙的深端有一个以微丝为核心的短质架状结构。我们认为，上皮裂解涉及裂隙底部细胞的动态运动，并在裂隙细胞内形成搁板。

We cultured the rudimental submandibular gland (SMG) of mice with a non cell-permeable fluorescent tracer, and observed cell behavior during epithelial branching morphogenesis using confocal time-lapse microscopy. We traced movements of individual cells as shadowgraph movies. Individual epithelial cells migrated dynamically but erratically. The epithelial cleft extended by wiggling and separated a cluster of cells into two buds during branching. We examined the ultrastructure of the clefts in SMG rudiments treated with the laminin peptide A5G77f, which induces epithelial clefting. A short cytoplasmic shelf with a core of microfilaments was found at the deep end of the cleft. We propose that epithelial clefting involves a dynamic movement of cells at the base of the cleft, and the formation of a shelf within a cleft cell.