Figure 2.

Lamination defects and loss of mitral cells in the OB in Rb−/− mice during late development. Immunostaining against PSA-NCAM performed on sagittal sections (A–B′) at E17.5 and showing aberrant lamination inside the OB, primarily affecting the IPL, ML, and EPL in the absence of Rb. (C–E′) Double staining against PSA-NCAM and GABA (gamma-amino-butyric acid) showing scattered GABAergic interneurons inside the IPL and ML with loss of clear boundaries between these layers in Rb−/− vs. Rb+/− mice (arrowheads in C′–F′). ^* in B′ depicts the presence of axonal guidance defects inside the ONL. (F,F′) are higher magnification images of regions shown in (E,E'), respectively. (G–H′) Staining with Reelin, marker of the proximal dendrites of mitral cells, performed on sagittal sections at E15.5 (G,G′) and P0 (H,H′) and showing gradual degeneration of the ML in Rb−/− mice compared with Rb+/− mice at birth. (I) Graph depicting the numbers of GABAergic neurons mislocalized in the IPL and of Reelin-positive cells in the ML in both genotypes t-tests, ^*p < 0.05. Scale Bar = 100 μm. GCL; Granule Cell Layer, GL; Glomerular Layer, ML; Mitral Layer, IPL; Internal Plexiform Layer, EPL; External Plexiform Layer, ONL; Olfactory Nerve Layer.