Increased spontaneous apoptosis in the Cdc42GAP-deficient fetal livers. Female heterozygous mice were timed for pregnancy and intraperitoneally injected with 100 μg BrdU/g body weight at E14.5. One hour after BrdU incorporation, the mice were killed and then underwent transcardial perfusion. Fetal livers of the embryos were dissected and embedded in paraffin while genotyping was carried out in parallel. Five-micrometer sections were deparaffinized and examined by anti-BrdU (A) or TUNEL (B) immunofluorescence microscopy. Right panels show quantification of at least 6 fields of the anti-BrdU or TUNEL fluorescence section shown in the left panels. Data are representative of 3 independent measurements.