Figure 1.

Conditional deletion of Smad4 in mouse hippocampus and normal spine density in CA1 of Smad4 mutants. A–D, Confirmation of deletion of Smad4 in adult mouse hippocampus by in situ hybridization. A, Smad4 mRNA is detected in 3-month-old control mouse hippocampus by antisense probe. B, With sense control probe, Smad4 could not be detected in the wild-type adult brain. C, Under higher magnification, Smad4 could not be detected from CA1 of Smad4 KO mice. D, Smad4 was still highly expressed in the habenulae of the same section. E, F, Golgi staining showed apical tertiary dendrites of CA1 pyramidal neurons from Smad4 KO and control mice. Scale bar (in F): A, B, 100 μm; C, D, 25 μm; E, F, 10 μm.