Figure 3.

Abnormal differentiation of neural progenitors in Gfap^+/R236H hippocampus. A, EdU injection protocol and tissue collection time line for cell fate analysis. Arrows indicate injection time points every 4 h for saturated labeling of cycling progenitors at 10 weeks of age, followed by tissue collection 28 d postinjection. B–D, Analysis of EdU-labeled cell types 4 weeks after injection shows both new neurons (B) and astrocytes (C) in the dentate gyrus of Gfap^+/+ mice as shown by costaining with NeuN and S100β, respectively. Unidentified EdU⁺/NeuN⁻/S100β⁻ cells were also apparent in Gfap^+/+ mice (D). E, F, In Gfap^+/R236H mice, this unidentified phenotype accounted for the majority of EdU-labeled cells (F), although many EdU⁺ cells were identified as S100β⁺ astrocytes (E). n = 5 male mice at 14 weeks of age per genotype. Scale bar, 10 μm. G, Gfap^+/+ mice show a normal distribution of neuronal and astroglial EdU⁺ cell types in the granular layer of the dentate gyrus (DG), as well as a population of unidentified EdU⁺ cells at 4 weeks after EdU labeling. Gfap^+/R236H mice show a lack of NeuN⁺ cells with the majority of EdU⁺ cells negative for either NeuN or S100β. H, The overall number of EdU labeled cells in the granular layer is increased in Gfap^+/R236H mice at 4 weeks postlabel compared with Gfap^+/+ mice. Although EdU⁺/NeuN⁺ neurons are depleted, EdU⁺/S100β⁺ astrocytes and especially NeuN⁻/S100β⁻ cells are increased in mutant mice. *p < 0.05, **p < 0.01, ***p ≤ 0.001, two tailed t test, n = 5 male mice at 14 weeks of age per genotype. I, Immunolabeling shows the presence of EdU⁺/GFAP⁺/S100β⁻ cells in the SGZ of Gfap^+/R236H mice. Scale bar, 10 μm.