Newly born mesenchymal cells disperse through a rapid mechanosensitive migration

Summary Embryonic mesenchymal cells are dispersed within an extracellular matrix but can coalesce to form condensates with key developmental roles. Cells within condensates undergo fate and morphological changes, and induce cell fate changes in nearby epithelia to produce structures including hair follicles, feathers or intestinal villi. Here, by imaging of mouse and chicken embryonic skin, we find that mesenchymal cells undergo much of their dispersal in early interphase, in a stereotyped process of displacement driven by three hours of rapid and persistent migration, followed by a long period of low motility. The cell division plane and the elevated migration speed and persistence of newly born mesenchymal cells are mechanosensitive, aligning with tension in the tissue. This early G1 migratory behaviour disperses mesenchymal cells and allows the daughters of recent divisions to travel long distances to enter dermal condensates, demonstrating an unanticipated effect of a cell cycle sub-phase on core mesenchymal behaviour. Highlights After mesenchymal cell division the speed and persistence of daughter cell migration is elevated for 180 minutes Mesenchymal cell division and migration are directed by tissue tension Newly born mesenchymal cells are uniquely responsive to tissue strain Newly born mesenchymal cells are preferentially recruited to dermal condensates Increased dispersal of newly born cells enables long distance travel to dermal condensates Graphical abstract