Fig. 2

Fig. 2. Mutation of kcnb1 causes defects in the developing ear. At 28 hpf (A, B) and 3 dpf (C, D) kcnb1^−/− mutants develop smaller ears and otoliths compared with wildtype controls. Fused otoliths in mutant ears at 3 dpf are shown (arrow). A′-D′, The ET33-mi2A transgenic line was used as a background to characterize inner ear morphology. Mutants developed all main elements of the inner ear despite the small size of mutant ears. E-G’’ Morphometric analysis of the size of the ears and otoliths at 28 hpf and 3 dpf. Both otoliths were small in 28 hpf mutants compared with the wildtype controls. By 3 dpf, the utricular otolith reached the same size as in wildtype controls, unlike the saccular otolith, which remained small. Data are expressed as mean ​± ​SEM, unpaired Student’s t-test. Imaging was performed using light-sheet fluorescence microscopy (20 ​× ​objective). ac, anterior crista; dpf, days post fertilization; hpf, hours post fertilization; lc, lateral crista; pc, posterior crista; sag, VIII statoacoustic ganglion; scc, semicircular canals; so, saccular otolith; uo, utricular otolith.