Differential genetic interaction with Apoer2^null and Vldlr^null mice in the cerebral cortex and hippocampus. A, Reln^CTRdel/Apoer2^null double-homozygote mice, but not Reln^CTRdel/Vldlr^null double-homozygote mice, display reeler-like cortical layer inversion. Reln^CTRdel/Vldlr^null mice appear similar to Reln^CTRdel and Vldlr^null mice without inversion. Sagittal sections of P21 brains were immunostained with anti-CUX1 and anti-CTIP2 antibodies. White dotted lines indicate the pial surface. Scale bar, 250 μm. B, Reln^CTRdel/Apoer2^null double-homozygote mice display the marginal zone invasion. Reln^CTRdel/Vldlr^null, Reln^CTRdel, and Vldlr^null mice appear similar to each other with the marginal zone invasion. Scale bar, 100 μm. C, Reln^CTRdel/Apoer2^null double-homozygote mice, but not Reln^CTRdel/Vldlr^null double-homozygote mice, display reeler-like hippocampus. Nissl staining images of P21 brain coronal sections are shown. Scale bar, 500 μm.