Live Imaging of Epithelial-Mesenchymal Transition in Mesoderm Cells of Gastrulating Drosophila Embryos.

Epithelial-mesenchymal transitions (EMTs) drive the generation of cell diversity during both evolution and development. More and more evidence has pointed to a model where EMT is not a binary switch but a reversible process that can be stabilized at intermediate states. Despite our vast knowledge on the signaling pathways that trigger EMT, we know very little about how EMT happens in a step-wise manner. Live imaging of cells that are undergoing EMT in intact, living, animals will provide us valuable insights into how EMT is executed at both the cellular and molecular levels and help us identify and understand the intermediate states. Here, we describe how to image early stages of EMT in the mesoderm cells of live Drosophila melanogaster embryos and how to image contractile myosin that suspends EMT progression.