Fig. 3. E11.5 (A,A'), E12.5 (B-C'), E15.5 (D,D') and E18.5 (E-F') coronal (A-D') and saggital (E-F') sections of wild-type (A-F) and Id4^-/- (A'-F') telencephalon are compared. Immunofluorescence was detected using the antibodies listed above each panel (A,A',D-E') and in situ hybridization was performed using the S-35-labeled riboprobes listed above each panel (B-C',F,F'). A pan-neuronal marker, MAP2 (A,A'), shows reproducibly increased expression in the mutant dorsomedial cortex (arrowhead). Markers of differentiating neurons, NeuroD (C,C') and Tbr2 (see Fig. 2D,D'), also show increased expression in the dorsomedial mantle (arrowheads in C,C'). TBR1 expression marks differentiating cortical neurons that will form deep cortical layers (D-E'). Arrowheads in F,F' indicate disorganized cortical layers and areas. hp, hippocampus; ctx, neocortex; LV, lateral ventricle; VP, ventral pallium; st, striatum.