Fig. 1.
Cortical development in ErbB2/B4-CNSko mice. (A) Immunopreciptiation of ErbB2 and ErbB4 from E14 and P0 brain extracts followed by Western blotting demonstrated an absence of ErbB2 and ErbB4 proteins; IP, immunoprecipitation. (B) Polymerase chain reaction (PCR) analysis of CRE-mediated recombination with DNA from P0 brains. In ErbB2/B4-CNSko mutants, the hGFAP-CRE transgene was detected, as well as a 170-kb (ErbB2) and a 507-kb (ErbB4) band indicating recombination of floxed alleles. (C) Brain size and morphology were unchanged in ErbB2/B4-CNSko mice at P249. (D) Sagittal brain sections at P38 stained with Nissl revealed no defects in cortical layers (roman numerals) and hippocampal structure. (E) Sagittal sections stained with NeuN (red) at P38, Cux1 at P256 (green), and Tbr1 at P249 (green). Nuclei were stained with Topro-3 (blue). (F) No differences were seen in NeuN, Cux1 or Tbr1-positive neurons in ErbB2/B4-CNSko mice (NeuN [cells/mm2]: WT 2665 ± 139, ErbB2/B4-CNSko 2630 ± 140, P > 0.05; Cux-1: WT 2015 ± 62, ErbB2/B4-CNSko 2052 ± 62, P > 0.05; Tbr1: WT 2257 ± 80, ErbB2/B4-CNSko 2192 ± 71, P > 0.05). (G) Coronal sections stained with the radial glia marker RC2 (green) and with antibodies to laminin-α2 (red) at embryonic ages E16 and E18. No difference in the gross morphology of radial glia was detected. (H) Immunoblotting for GFAP using brain extracts from P0 mice. Actin served as loading control. Scale bars, 50 μm