Fig. 8. Cell proliferation and programmed cell death in the developing lateral canal region of Gli3^-/- and Shh^-/- mutants. Bmp4 expression (A,D,G), BrdU labeling (B,E,H) and TUNEL staining (C,F,I) in Gli3^+/- (A-C), Gli3^-/- (D-F), and Shh^-/- (G-I) inner ears at 11.75 dpc. (A-C) Robust cell proliferation and little programmed cell death are observed in the primordial lateral canal region in Gli3^+/- ears. The presumptive lateral crista is Bmp4 positive. (D-F) Markedly decreased cell proliferation and increased programmed cell death (arrowheads) are found in the lateral wall of the inner ears of Gli3^-/- mutants. (G-I) In Shh^-/- mutants, no changes in cell proliferation (H) and programmed cell death (I) are observed in the primordial lateral canal area. Yet, there is increased cell death in the medial and anterior wall of the inner ear (I,I', arrowheads). Orientations: A, anterior; L, lateral. Scale bar: 100 µm.