Decreased neuronal differentiation and increased apoptosis in the Sox2-deficient olfactory epithelium. (A) Tuj1 and aCaspase3 immunofluorescence in E9.5 wild-type, heterozygous Sox2flox/+ and Sox2 cKO mutants. Arrowheads indicate aCaspase3+ cells. (B) No change in the number of Tuj1+ neurons or aCaspase+ apoptotic cells between the wild-type and heterozygous mice are detected. In contrast, the generation of Tuj1+ neurons is decreased and aCaspase3+ apoptotic cells are increased in Sox2 cKO mutants compared with wild-type and heterozygous mice. Statistical analysis of the cell counts in comparison to the total cell number in the olfactory epithelium of E9.5 wild-type (n=7), heterozygous (n=6) and Sox2 cKO mutants (n=5) are as follows. For Tuj1, wild type versus Het P=0.8173, wild type versus KO P=0.0263, Het versus KO P=0.0412. For aCaspase3, wild type versus Het P=0.7847, wild type versus KO P<0.0001, Het versus KO P<0.0001. Error bars represent s.e.m. Student's t-test, *P<0.05, ***P<0.0001. Scale bar: 100 µm.