Fig. 2

Ablation of Yy1 after E12.5 does not influence cortical development. a Genotype of mice and experimental strategy used to induce ablation of Yy1 at different developmental stages. b Later stage tamoxifen-induced ablation of Yy1 ameliorates the decrease in cortex size compared with Yy1cKO cortices (Fig. 1b). c Measurement of cortical length (L) and width (W) as indicated in b. For representative picture of E18.5 Yy1cKO cortex, see Fig. 1b. *p < 0.05. d Experimental strategy to ablate Yy1 at E12.5 in Yy1iKO embryos (for Fig. 2e–k). e–h Immunostaining and quantification for pHH3+ cells at E14.5 (e, g) and E15.5 (f, g) in E12.5-ablated Yy1iKO embryos. h depicts the ratio of apical vs. basal pHH3+ cells. The number of pHH3+ cells is normalized to 600 μm ventricular zone length. i–k Ablation of Yy1 at E12.5 elicits cleavage of Caspase 3 (cCasp3) at E14.5 (i, k) but not at E15.5 (j, k). Note that red signals visible at E15.5 are blood cells. l Experimental strategy to ablate Yy1 at E13.5 in Yy1iKO embryos (for Fig. 2m–q). m–o The total number and ratio of apical vs. basal pHH3+ cells remains unchanged upon late ablation of Yy1 at E13.5. The number of pHH3+ cells is normalized to 600 μm ventricular zone length. p, q Ablation of Yy1 at E13.5 only induces cell death in a minority of cells (indicated by arrows, remaining red signals are blood cells). Nuclei are counterstained with DAPI. Scale bars represent 1 mm (b), 50 µm (e, f, i, j, m, p). Comparisons were performed using ANOVA (Tukey’s multiple comparisons test) (c) and two-tailed unpaired Student’s t test (g, h, k, n, o, q). Data are the mean ± standard deviation. ns = not significant