Figure 5
From: Topographical curvature is sufficient to control epithelium elongation
Curvature-dependent orientation of key morphogenetic mechanisms. (a) Cell trajectories during 24 h of growth on Topo I (see also Supplementary Movie 1). Note that cells initially starting transversally turns toward the longitudinal axis. (b) Average cell stretching (Aspect Ratio) and cell alignment with topography within the epithelial colony (mean + SEM). Five separated fields per colony, four independent colonies per topography. Non parametric Kruskal–Wallis test, *P < 0.05. (c) Schematic of the positional parameters quantified for mitosis. θ angle: orientation of the mitotic spindle relatively to the topography longitudinal axis ω angle: angular coordinate of the dividing cell using the longitudinal axis as reference axis and the colony centroid as origin. (d) Distribution of the mitotic spindle orientation θ (bin width: 10°) 300–400 mitosis from 4 independent colonies for each topography. The dotted lines separate the angles below 45° (indicating an alignment with the substrate longitudinal axis) and above 45° Kruskal–Wallis non-parametric test shows a statistical difference between medians P < 0.0001. (e) Distribution of the angular coordinate ω of cells in mitosis (bin width: 10°), 300–400 mitosis from 4 independent colonies for each topography. Kruskal–Wallis non-parametric test shows a statistical difference between medians P < 0.0001. (f) Model of the epithelial anisotropic growth. The surface longitudinal axis is oriented horizontally. Transversally facing colony borders are hampered in a curvature-dependent fashion. Longitudinal orientation of cell migration and cell proliferation sustain the growth of longitudinally facing borders, leading to the anisotropic deformation of the colony.
