Fig. 6: Loss of mechanotransduction in HCs of Tmie cKO utricles does not affect its neuronal segregation pattern.

a–c’ Emx2 (a–c) and Tmie (a’–c’) transcripts in sections of Tmie^+/− (a, a’, n = 3), Gfi1^cre; Tmie^F/− (b, b’, n = 2), and Emx2^cre; Tmie^F/− (Tmie cKO, c, c’, n = 3) utricles. Tmie transcripts are absent in the entire sensory epithelium of Gfi1^cre; Tmie^F/− utricle (b’) but are absent only in the Emx2-positive lateral region (a–c, black dotted region) of Emx2^cre; Tmie^F/− utricles (c’). d–f FM1-43 staining in live utricles of Tmie^+/− (d, n = 5), Gfi1^cre; Tmie^F/− (e, n = 3), and Emx2^cre; Tmie^F/− (f, n = 4) inner ears at P0. FM1-43 is present in the entire sensory epithelium of Tmie^+/− (d), absent in Gfi1^cre; Tmie^F/− (e) and absent only in the lateral region of Emx2^cre; Tmie^F/− utricle (f). Outline of the utricular macula is demarcated with a white dotted line and the lateral region is marked with a yellow dotted line (d–f). g–l Utricles with dye tracing from the cerebellum (green) and brainstem (magenta) of Tmie^F/− (g, n = 2; j, n = 3), Gfi1^cre; Tmie^F/− (h, n = 2; k, n = 3), and Emx2^cre; Tmie^F/− (i, n = 3; l, n = 3) at E16.5 day (g–i) and P0 (j–l). Neuronal tracing from the cerebellum and the brainstem labeling the respective lateral and medial utricle are normal among all three genotypes at E16.5 and P0. Scale bar = 200 μm in a, applies to b, c; 100 μm in a’, applies to b’, c’, and 100 μm in d–l.