Fig. 4

Yy1 inactivation in MHB neuroepithelium caused apoptosis and p53 accumulation. a The percentage of debris in the gated dissociated mes/r1 cells from flow cytometry analysis. b-e TUNEL assay showing significant elevated cell apoptosis in the mutant MHB region at E9.5 (b, c) and E10.5 (d, e). f Statistical analysis showing dramatic increased apoptotic rate in the mutant MHB region. For E9.5, N = 4; For E10.5, N = 7. Unpaired two-tailed t-test. ***, p < 0.001. g, h Immunostaining using antibody against Cleaved Caspase 3 showing activation of Caspase cascade in mutant MHB neuroepithelium at E10.5. i, j Immunostaining showing nucleus accumulation of p53 (arrowheads) in the Yy1-deleted mes/r1 NECs at E10.5. k Relative expression level of Trp53 and altered p53 pathway downstream genes. Unpaired t-test. ***, p < 0.001; *, p = 0.004. l, m Immunofluorescent staining showing the increased expression of the proapoptotic effector Bax in Yy1-ablated MHB neuroepithelium