Inactivation of Rbpj results in severe gliogenesis defects. (A-F) BFABP immunostaining of wild-type (WT) and Rbpj CKO DRG at E11.0 (A,B), E11.5 (C,D) and E12.5 (E,F). Compared with wild type controls, BFABP expression in Rbpj-deficient DRG is undetectable at E11.0 (B) and E11.5 (D), and only a small number of labeled cells are observed at E12.5 (F). Arrows point to DRGs. (G-X) Double immunolabeling of P75 and Sox10 at E10.5 (G-L), E11.5 (M-R) and E12.5 (S-X). P75/Sox10 co-labeled cells are observed in both wild-type and CKO DRGs at E10.5 (G-L), and there were no obvious differences in the number of co-labeled cells between wild-type and CKO. In wild-type DRG at E11.5 (Q) and E12.5 (W), P75 and Sox10 are distinctly expressed in separate populations of cells, whereas many P75/Sox10 co-labeled cells are present in CKO DRG at these stages (R,X). (W,X) High magnification views of the areas delineated by white rectangles in (S,U) and (T,V), respectively. Arrows indicate cells that express P75 alone, arrowheads indicate cells that express Sox10 alone, and double arrows indicate P75/Sox10 co-labeled cells. (Y) Statistical analysis of numbers of P75/Sox10 co-labeled cells in wild-type and Rbpj CKO DRG at E10.5, E11.5 and E12.5. Error bars represent standard error of the mean; *P < 0.05. Note that P75/Sox10 co-labeled cells located at the nerve root (asterisks in G,H,M,N) were not counted. Scale bars: 100 μm in (A-V); 20 μm in (W,X).