Identification of a Novel ENU-Induced Mutation in Mouse Tbx1 Linked to Human DiGeorge Syndrome

Figure 3

The ENU706 mice had no obvious defects in hair cell mechanotransduction. (a) The ABR threshold was box-whisker plotted in 4 categories: wild-type male (WT M, 20.0 ± 2.4 dB SPL, 8 males tested, 8 right ears plus 1 left ear), heterozygous male (ENU706+/− M, 38.7 ± 3.9 dB SPL, 11 males tested, 11 right ears, and 8 left ears), wild-type female (WT F,  dB SPL, 8 females tested, 9 right ears, and 1 left ear), and heterozygous female (ENU706+/− F,  dB SPL, 13 females tested, 13 right ears, and 10 left ears). The “” numbers were counted twice if both ears were measured. Data shown as mean ± SEM. Statistical significance () was determined by Student’s two-tailed unpaired -test. (b) The ABR threshold was plotted against age. The data pooled from left and right ear were shown (WT, 20 mice tested, 20 right ears, and 3 left ears; ENU706+/−, 24 mice tested, 24 right ears, and 19 left ears). (c) The mechanotransduction currents were measured in outer hair cells of ENU706 heterozygous mice and control littermates (cell number shown in the panel). Data shown as mean ± SD. A set of mechanical deflections from −400 nm to 900 nm at 100 nm step were applied to hair bundle to generate mechanotransduction currents in hair cells. In all panels, control was shown in black and ENU706 in red. (d) Scanning electron microscopy showed the hair bundles of apical-middle outer hair cells were relatively normal in an ENU706 heterozygous mouse. Scale bar: 5 μm.

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