Fig. 4.

Akt kinase activity in postmitotic neurons regulates radial migration. (A–D) The brains of Nex^Cre/+ embryos at E15.5 were subjected to in utero electroporation with Cre-dependent expression plasmids for GFP alone (Control) or for GFP together with Akt1 KN (A) or Akt1 WT (C). GFP fluorescence in coronal brain sections prepared at E19.5 (A) or E18.5 (C) was analyzed. Nuclei were stained with Hoechst 33342. (Scale bars, 100 µm.) The corresponding distributions of GFP⁺ cells in the neocortex were determined as means ± SEM for the indicated number (n) of brains analyzed (B and D). (E and F) The brains of E15.5 Nex^Cre/+ embryos were subjected to in utero electroporation with Cre-dependent expression plasmids for GFP alone (Control) or for GFP together with Akt1 KN (E) or Akt1 WT (F), and cortical slices prepared at E18.5 were monitored for the migration of GFP⁺ cells for up to 20 h. The average speed of radial migration was determined for individual neurons. Data are means ± SD for 31 or 32 neurons. *P < 0.05, **P < 0.01, ***P < 0.001 (Student’s t test) versus the corresponding control value.