Fig. 3: Hpdl knockout (KO) mice display early lethality, smaller brain sizes, and cellular apoptosis.

(a) Kaplan–Meier curve displaying the survival probability of Hpdl heterozygous mice (n = 10, blue) versus Hpdl KO mice (n = 6, red). (b) Graph depicting body weight measurements of Hpdl heterozygous mice versus Hpdl KO mice at postnatal days 0, 2, 5, and 9. P values were obtained by an independent t-test. (c) Whole-brain images of wild-type (WT) versus Hpdl KO mice at P0 and P10. Scale bar: 1 mm (d) Coronal sections of P9 WT and KO mouse brain were stained for DAPI (blue) and Cleaved Caspase 3 (CC3, green). The P9 KO shows strong CC3+ immunoreactivity. Note the absence of CC3 immunoreactivity in the P9 WT. Scale bar: 50 µm (e) Quantification of CC3+ cells in Hpdl WT vs KO mouse brain per 500-μm column. Statistical analysis (two-way analysis of variance [ANOVA]) was performed between the categories. N = 3 independent experiments with two sections per mouse quantified (****P < 0.0001). (f) Coronal sections of P9 KO mouse brain were stained for DAPI (blue) and CC3 (green) in combination with either CTIP2 (red), OLIG2 (red), or GFAP (red). White arrows depict colocalization of the cell identity markers with CC3. Scale bar: 50 µm. (g) Quantification of the number of CTIP2+, OLIG2+, or GFAP+ cells which were also CC3+. Analysis shows CTIP2+ cells to be most affected, followed by GFAP+ cells, followed by OLIG2+ cells. N = 2 independent experiments. Two sections per mouse were used for quantification.