Figure 11.

A receptor–ligand-based Turing model for lung branching morphogenesis. (a,b) The regulatory network shown in figure 3f gives rise to a Turing pattern and results in distributions of FGF10 (colour code: red, highest; black, lowest) and SHH (black and white contour line plot) on bud-shaped domains as characteristic for (a) bifurcation or (b) lateral branching events. (c) The FGF10 concentration profile along the lung bud. (d) An extended network that includes also FGF9 also reproduces the observed patterns of smooth muscle (SM) formation from progenitors (PR) and Vegfa expression during lung branching morphogenesis. (e) Smooth muscles (colour code) emerge in the clefts between lung buds (contour lines mark FGF10 concentration levels) as the lung bud grows out. (f) Vegfa expression, an inducer of blood vessel formation, emerges in the distal subepithelial mesenchyme. (a–c) Adapted from Menshykau et al. [50]; (d–f) adapted from Celliere et al. [60].