Malformation of the radial glial scaffold in the dentate gyrus of reeler mice, scrambler mice, and ApoER2/VLDLR-deficient mice.

We studied the postnatal development of the radial glial scaffold in the dentate gyrus of reeler mice, lacking the extracellular matrix protein Reelin, in scrambler mice, deficient in the intracellular adaptor protein disabled1 (Dab1), which is required for the transmission of the Reelin signal into the cell, and in mutant mice lacking the Reelin receptors apolipoprotein receptor 2 (ApoER2) and/or the very low density lipoprotein receptor (VLDLR), known to transmit the Reelin signal via Dab1. By immunolabeling for the glial fibrillary acidic protein (GFAP), we show that a regular dentate radial glial scaffold fails to form in mutants deficient of Reelin, Dab1, and VLDLR and ApoER2. Mutant mice lacking only one of the Reelin receptors, VLDLR or ApoER2, display a gradual expression of the radial glial defects seen in mutants that lack both receptors. Our results suggest that Reelin signaling via ApoER2, VLDLR, and Dab1 is required for the formation of a regular radial glial scaffold in the dentate gyrus.