Figure 5

Expression of Cyp26 genes is altered in TCre-KO embryos. Cyp26a1 and Cyp26c1 expression detected by whole mount in situ hybridization at E10.5 in control and TCre-KO embryos (A-H). The plane of section in B, D, F and H is marked in A, C, E, and G, respectively. Cyp26a1 expression in the lateral POM (arrows in B) is absent in TCre-KO mutants (arrows in D), and appears shifted to a more ventral position (compare A an C). Cyp26c1 expression is strongly reduced in the mesenchyme of TCre-KO mutants (compare F and H), but 1^st arch expression is unaffected (asterisk in E and G). At E11.5, Cyp26a1 expression remains shifted medially in TCre-KO mutants compared to controls (I-L), especially in posterior sections through the growing cochlear duct (arrows in J and L). Cyp26c1 is strongly reduced in the ventral POM at this stage (M-P), but remains present in the otic epithelium (arrows in M and O). A dotted circle outlines the otic vesicle (ov) in A, C, E, G. Scale bar in P is 200 μm and applies to all panels except A, C, E, G.