Figure 5

E2-2 alteration influences cell cycle exit of progenitors in vivo . (A) E2-2 overexpression increased cell cycle exit (EdU⁺Ki67^–/EdU⁺) among the progenitor cell population (non-RGC) compared to control conditions at 2 dpe (100 ± 7.5 vs. 184.9 ± 18.0). Confocal micrographs show representative non-RGCs (GFP⁺) having cycled within 24 h prior to sacrifice (EdU⁺) and having re-engaged (Ki67⁺) or exited the cell cycle (Ki67^–), respectively. (B) In contrast, knock-down of E2-2 decreased cell cycle exit within the progenitor pool as illustrated by the increased Ki67 immunoreactivity among EdU⁺ non-RGCs, when compared to control conditions (Scrambled) (100 ± 7.8 vs. 65.8 ± 1.3). (C, D) E2-2 overexpression also increased the number of Dcx⁺ neuroblasts (100 ± 0.5 vs. 128.1 ± 2.9) (C), whereas the number of Ascl1⁺ type-C cells remained unchanged (100 ± 6.4 vs. 94.6 ± 9.2) (D). (E) Percentage of cell type composition (i.e., type-B = RGC, type-C = Ascl1⁺, type-A = Dcx⁺) upon E2-2 overexpression, when compared to an empty control plasmid at 2 dpe (30.7 ± 4.6 vs. 14.2 ± 2.3, 30.0 ± 1.2 vs. 35.6 ± 2.5, 39.2 ± 0.3 vs. 50.2 ± 1.8, respectively). (F) Summary model: E2-2 orchestrates neurogenesis progression within the murine forebrain. P values: *P <0.05; **P <0.01; ***P <0.001. Quantifications were normalized to control conditions (A–D). Scale bars: A &B, 20 μm.