Fig. 4. Effects of caNotch on cortical progenitors. pCAG-EYFP (A,B) or pCAG-ExNotchZ (C,D,F-J,L,M) was transfected at E13.5. (A-D,F,G) Embryonic brains were labeled at E14.5 for 2 hours (A-D) or 15 hours (F,G) with BrdU. Green and red signals show immunostaining with anti-GFP and anti-BrdU antibodies, respectively. (E) The ratio of BrdU⁺ cells in the total population of EYFP⁺ cells or EYFP⁺/CaNotch⁺ cells of 2-hour-labeled brains. Each ratio was calculated from three brains. (H-J) An E15.5 brain, 2 days after transfection. Green and red signals show EYFP fluorescence and immunostaining with the RC2 antibody, respectively. The ratio of RC2⁺ cells in the total population of EYFP⁺ cells was calculated from three brains. (K-M) TUNEL assay performed on the E15.5 brain. The areas of the transfected hemisphere (L,M) and the opposite non-transfected hemisphere (K) of an electroporated brain are shown. Green signals show EYFP fluorescence. Transfected green cells were not detected in the non-transfected hemisphere (K). A,B; C,D; F,G; H-J; and K-M each show the same section. B,D,G,J,K and M are merged views. CP, cortical plate; LV, lateral ventricle; VZ, ventricular zone. Scale bars: 50 µm for A-D,F,G; 20 µm for H-J; 100 µm for K-M.