Extended Data Figure 6. p53^3KR/3KRMdm2^−/− mice are embryonic lethal.

a, Representative gel images for genotyping of Mdm2 status in p53^3KR/3KR background mice. b, Summary of numbers of live embryos and pups recovered from p53^3KR/3KRMdm2^+/− intercross breeding. c, Haematoxylin and eosin (H&E) and immunohistochemistry staining of p53 and TUNEL assay on E7.5 embryos of indicated genotype (magnification, ×20). d, Percentage of cells with positive TUNEL or BrdU were determined by counting 100 cells in each section from three different embryos. Error bars, s.d.; N.S., not significant. e, Whole-embryo extracts from E9.5 embryos were used for western blot. As positive controls, thymus protein lysate from irradiated (IR) wild-type mouse (8 Gy) was used. f, Messenger RNA expression levels of Puma were determined by RT–qPCR using E9.5 embryos with indicated genotype (n=3 for p53^3KR/3KRMdm2^+/+ and n=5 for p53^3KR/3KRMdm2^−/−; error bars, s.d.; N.S, not significant). g, Representative images of whole-mount senescence-associated β-galactosidase staining using E9.5 mouse embryos with indicated genotype (magnification, ×2). h, Same protocol as in g was used to stain control wild-type embryos and embryos of HAUSP heterozygous knockouts, which express β-galactosidase⁴⁰ (magnification, ×2). i, Late passage senescent wild-type MEFs were stained for senescence-associated β-galactosidase activity using the same protocol as in g (magnification, ×10).