Fig. 3.

Origins of flow organisation. A) Flow organisers. From left to right: Attractors and repellers of the tissue flow, territories of directed and stochastic cell intercalation and myosin cables B) Cell behaviours that drive epithelial tissue flows, cell intercalation, cell division and ingressions. Division and ingression also contribute to cell rearrangements since they create changes of epithelial topology. C) Mechanism of contraction propagation based on tension dependent stabilisation of apical junctional myosin. From top to bottom: 1) The apical contraction of an individual cell due to a local accumulation of myosin, 2) results in the stretching of neighbouring cell junctions. The increase in tension produced by the stretching leads to the local stabilisation of myosin in these cells resulting in 3) apical contraction in these cells and propagation to further neighbours.