Fig. 1. Retinoid receptors and RA effects in P15 mouse SVZ neurosphere (NS) cultures. (A) RT-PCR reveals that secondary NS expanded for 6 days express mRNA for RAR, ß, and RXR, but not RXR retinoid receptor subtypes. (B,C) Differentiation of NS for 7 DIV with RA increases ß-tubulin-immunoreactive neurons (C) compared with vehicle (B). (D-G) BrdU (red)/ß-tubulin (ß-tub; green) double labeling (arrows) demonstrates that RA treatment of differentiating NS for 4 DIV increases neuroblast proliferation (E,G) versus vehicle (D,F). (H,I) Activated caspase-3 (casp 3; green) immunolabeling (arrows) shows no influence of RA treatment (I) on cell death versus control (H). Bis-benzimide counterstain in blue. Scale bars: in I, 100 µm for A,B and 50 µm for D,E,H,I; in G, 20 µm for F,G.