Figure 3: Migration of CR cells is inhibited by Sema3E in brain slices.

(a) Schematic representation of the assay. The boxed region in a is shown in (b–e). eGFP-positive CH from Actin-eGFP embryos was transplanted in replacement of original hem of Sema3E^+/+ (b,c) and Sema3E^o/o (d,e) E13.5 brain slices, which were further treated with SEAP (b,d) or Sema3E-AP (c,e) for 48 h in culture. Quantification of the number of CR cells identified as eGFP (green)/CALR (red)-positive cells exiting from the hem and migrated distance is shown in (f,g). The number of the eGFP-positive migrating cells (f) and the migrated distance (g) under each condition are plotted. Plots show mean±s.e.m. Sema3E^+/+ (number of cultures:+SEAP, n=9;+Sema3E-AP, n=7); Sema3E^o/o (number of cultures:+SEAP, n=10;+Sema3E-AP, n=8). (h,i) Distribution of hem-derived CR cells from E12.5 Sema3E^o/o embryos confronted with meninges (Me) and treated with SEAP (h) or Sema3E-AP (i). Dotted lines indicate the border of the meningeal explant. (j–l) Quantification of the experiments in (h,i). The number of cell/culture and the distance is plotted. The proximal quadrant/distal quadrant (PQ/DQ) ratio is also shown in (l). Number of cultures:+SEAP, (n=15);+Sema3E-AP, (n=16). Plots show mean±s.e.m. *P<0.05, **P<0.01. Student’s t-test. Scale bars, 200 μm in b–e; 300 μm in h,i.