Fig. 5

Mosaic perturbation of RhoA and Rac function. a Transplantation experiment set-up: cells from ngn1:gfp donor embryos co-expressing mbCherry and a dominant-negative form of RhoA (DN-RhoA) or of Rac (DN-Rac), or mbCherry alone (controls) were transplanted into ngn1:gfp host embryos, in order to achieve a mosaic perturbation of RhoA or Rac function. b Examples of embryos showing transplanted cells spanning the whole OP in controls, and instances of ectopic posterior and anterior transplanted cells expressing DN-RhoA. The right panel shows a DN-RhoA+ cell occupying a lateral position in the host placode. Insets show individual cells or cell groups expressing DN-RhoA, co-stained with DAPI to show that these cells are alive. Scale bar: 50 µm. c Spatial distribution of transplanted cells at 24 s, in control (dark grey) and DN-RhoA (orange) conditions, and projections of the spatial distribution along the AP and ML axis. The reference point is defined as the position of the axon bundle on the brain surface. χ ²-tests are used to identify statistically different distributions (***p < 0.001). DN-RhoA+ cell distribution is more spread than that of control cells along the AP axis, but not along the ML axis, showing that DN-RhoA cell autonomously affects AP distribution of cells, but not their lateral dispersion. d Same analysis as in (c) with DN-Rac conditions in orange. Distributions are statistically different both along the AP axis and along the ML axis. As for DN-RhoA, DN-Rac+ cell distribution is more spread along the AP axis than in controls. Along the ML axis, DN-Rac+ cells distribute further laterally as compared to control cells, suggesting more efficient lateral movement