Nestin (B, C), Sox2 (E, F), and Id1/PECAM (H, I) immunostaining of the subgranular zone (SGZ) of 4-mo-old controls (B, E, H) and Nestin-CreERT2;Prox1F/F (C, F, I) mice treated with TM from P0 to P15. Graphs compare the number of Nestin+ (A), Sox2+ (D), and Id1+PECAM− (G) cells in P20, 2-mo-old, 4-mo-old, and 8-mo-old control (blue) and Nestin-CreERT2;Prox1F/F (red) mice treated with TM from P0 to P15. At P20, the number of Nestin+, Sox2+, or Id1+PECAM− NSCs is similar in controls and Nestin-CreERT2;Prox1F/F brains (A, D, G). However, after P20, the number of Nestin+ (A–C), Sox2+ (D–F), or Id1+PECAM− (G–I) cells is reduced in Nestin-CreERT2;Prox1F/F mice. Graphs compare the number of Nestin+ (J), Sox2+ (M), and Id1+ PECAM− (P) cells in 12-wk-old and 16-wk-old control (blue) and Nestin-CreERT2;Prox1F/F (red) mice treated with TM for 4 wk starting at 8 wk of age. The number of Nestin+, Sox2+, and Id1+ PECAM− adult NSCs was increased in 12-wk-old conditional mutant brains (J, M, P). At 16 wk, the number of Nestin+ (J, L), Sox2+ (M, O), and Id1+ PECAM- (P, R) cells is reduced in the SGZ of conditional-mutant mice. The percentage of Nestin+/b-Gal+ and Sox2+/b-Gal+ cells is similar in 12-wk-old (S) and 16-wk-old (T) control (blue) and Nestin-CreERT2;Prox1F/F (red) brains that carry the ROSA allele. However, the percentage of Tbr2+/b-Gal+ and Dcx+/b-Gal+ cells is reduced at both stages in the Nestin-CreERT2;Prox1F/F;ROSA SGZ (S, T). Data represent the mean number of positive cells per DG section ± SD. N = 4 brains. Paired t test. * p<0.1; ** p<0.01; *** p<0.001; **** p<0.0001. GCL, Ganglion cell layer. Scale bar in (B, C, E, F, H, I): 25 µm. Scale bar in (K, L, N, O): 100 µm. M, month; W, weeks. Scale bar in (Q, R): 50 µm.