Fig 3. Simulations including crawling-driven CE reproduce average LOCO-EFA coefficients.
A: Schematic of the filopodial-tension model with self-organized preferred direction. Green and blue arrows indicate the cells’ polarization directions. The highlighted cell s can extend filopodia within the shaded blue cone around its polarization direction. Such filopodia are currently attached to cells s1, s2 and s3, indicated by the link between the cell centers. The new polarization direction of cell s is the weighted average of its old polarization direction and the average polarization direction of cells s1, s2 and s3. The rightmost panel shows the new polarization direction of cell s as a blue arrow. The old polarization direction is indicated by a pink arrow. B: Example shapes resulting from a simulation with one cell type for 100, 25,000, 50,000, 75,000 and 100,000 Monte Carlo steps. C,D: Quantification of shapes resulting from simulations of crawling-driven CE. Shown are LOCO-EFA coefficients averaged over a population of shapes. The shaded areas (in the experimental data) and vertical bars (in the simulation data) indicate standard deviations. C: The interaction strength with the medium was varied. The pulling force was kept constant at 15. D: The pulling force was varied. The surface tension with the medium was kept constant at 5. E: Scatter plot of the scaled LOCO-EFA coefficients L3/L1 versus L2/L1 for the experimental data and simulations of crawling-driven CE with pulling force λF = 15 and surface tension γ(c, M) = 5. These parameters gave the smallest 2D Kolmogorov-Smirnov test statistic comparing experiment and simulation (D = 0.40, p = 9.3 ⋅ 10−9). F: Example of experimentally observed shape (bottom) with highly similar simulated shape (top) and their corresponding scaled LOCO-EFA coefficients L3/L1 and L2/L1. Bottom: a 96 h fixed gastruloid. Shown is the mid-plane of a z-stack. Cell nuclei were stained with DAPI. Scale bar: 200 μm.