Fig. 2. Early fragmentation of Ush1 mutant cochlear hair bundles during development. (A) Hair bundles of sensory cells from the cochlear basal turn of E17.5 wild-type and Ush1 mutant mice. Whole-mounts of the organ of Corti were stained with phalloidin to reveal F-actin in stereocilia. (B) Analysis of P0 cochlear hair cells from wild-type and Ush1 mutant mice by SEM. Note the fragmented aspect of the hair bundles, and sometimes also of the microvillar area, in the mutants. (C) OHC hair bundles in wild-type and Ush1 mutant mice at P0. Lateral links are visible between stereocilia from both wild-type and mutant hair cells (see insets), although they appear sparser and frequently disrupted in the mutants, especially Cdh23^v2J/v2J and Pcdh15^av3J/av3J. Scale bars: 2 µm in A,B; 1 µm in C.