Figure 2.

In silico simulation of apical constriction mimics microridge development in vivo. (A) Diagram of a periderm cell in homeostatic conditions with actin-filled microridges projecting from the apical surface. The underlying apical cortex is rich in actin (red filaments) and NMII (green bipolar mini-filaments) and attached to the cell membrane. (B) Diagram of a periderm cell undergoing apical constriction. NMII contraction in the apical cortex relieves tension in the attached cell membrane, allowing actin to protrude. (C) Cells from in silico simulations developed a long microridge at the cell border before microridge formation elsewhere on the apical membrane. Arrows in the inset image point to a similar structure in periderm cells expressing Lifeact-GFP before microridge development. (D) In silico simulation of apical constriction in our biomechanical model recapitulates the centripetal progression of microridge development observed in vivo. (E) Average change in apical area and average microridge length in 20 simulations. Scale bar, 10 µm (C).