Fig. 3. Co-cultivation of reeler (rl–/–) dentate gyrus with wild type rescues radial fiber orientation and neuronal lamination. (A) Schematic diagram illustrating the experimental design. The rat dentate outer molecular layer was co-cultured next to the reeler dentate gyrus to provide the reeler dentate gyrus with a reelin-containing zone in normotopic position. (B) NeuN staining of a rat hippocampal culture co-cultured with the reeler hippocampus, as indicated in A. Note the formation of a compact cell layer in the reeler dentate gyrus (arrow) adjacent to the rat outer molecular layer. Dashed line indicates border between the two cultures. The boxed area is shown in C and D at a higher magnification. (C) Boxed area shown in B, immunostained for GFAP. Note the long, vertically oriented radial fibers (arrowheads) in the reeler dentate gyrus adjacent to the rat outer molecular layer. The dotted line indicates the border between the cultures. (D) Same detail as is shown in C, counterstained for NeuN. Arrows indicate the compact cell layer formed in the vicinity of the rat outer molecular layer. Scale bars: 150 µm in B; 40 µm in C,D.