FIGURE 2.

Recombination in Aldh1L1-CreER^T2; GFP mice efficiently and specifically targets astrocytes but not neural stem cells in the adult dentate gyrus. (A) Schematic drawing showing the short-term tamoxifen pulse. Here, Aldh1L1-CreER^T2; GFP mice were injected with tamoxifen every 12 h (12 h) for five consecutive days and killed 2 h post-injection (2 h pi). (B) Representative pictures illustrate an overview of an immunohistochemically stained DG of adult Aldh1L1-CreER^T2; GFP mice. Arrows point toward GFP/GFAP/Aldh1L1 triple positive cells while arrowheads highlight non-recombined GFAP⁺/Aldh1L1⁺ astrocytes. The asterisk marks a non-recombined GFAP⁺ radial process of an adult NSC (DAPI in blue, GFP in green, GFAP in red, Aldh1L1 in white; scale bar = 20 μm). (C,D) The graphs show recombination efficiency in adult DG astrocytes and adult DG astrocyte subtypes (mean + SEM). (E,F) The graphs show recombination specificity in adult DG astrocytes and adult DG astrocyte subtypes (mean + SEM). (G) Overview image of an immunohistochemically stained Aldh1L1-CreER^T2, GFP transgenic mouse DG using antibodies against GFP (green), S100β (red), and Nestin (white) 2 h pi; DAPI is depicted in blue, scale bar = 20 μm. (H–K) Representative pictures of astrocytes of each DG layer in [(G); boxed areas] were chosen for magnification. Arrows point toward recombined GFP⁺ astrocytes (green) expressing S100β (red) in the molecular layer (H), the hilus (I), the granular zone (J), and the subgranular zone [SGZ; (K)] (scale bars = 20 μm). (L) Schematic drawing showing the long-term tamoxifen pulse. Here, Aldh1L1-CreER^T2; GFP mice were injected with tamoxifen every 12 h (12 h) for five consecutive days and killed 28 days post-injection (dpi). (M,N) Representative pictures of immunohistochemical staining against GFP (green) and DCX (white) and NeuN (red), respectively. Arrows point toward recombined GFP⁺ cells, which do not co-express either DCX or NeuN; DAPI is depicted in blue; scale bar = 20 μm.