Figure 2. Myosin VI expression and localization in Tailchaser hair cells.

(A–J) Expression of myosin VI (green) in wild type (A–D and I) and Tlc/Tlc (E–H and J) cochlear whole mount preparations, with filamentous actin labeled with rhodamine/phalloidin (red). Merged and corresponding green channel images are shown next to each other. Myosin VI-specific immunostaining can be detected in wild type and Tlc/Tlc stereocilia on inner (A–C, E, G, I, J) and outer (D, F, H) hair cells at P6 (A) and P70 (B–J) and appears to be outside of the stereocilia actin core. In wild type in the apical turn, myosin VI specific immunostaining is evenly distributed along the length of the stereocilium, with an increase at the base (A–D, I), while Tlc/Tlc stereocilia often show concentration of myosin VI-specific staining near stereocilial tips (E–H and J). In the middle turn of the cochlea, where hair cell degeneration was less pronounced, the immunofluorescence pattern was the same in inner (E) and outer (F) hair cells. Fused and elongated inner hair cells stereocilia in the basal turns of the cochlea showed a more diffuse pattern of myosin VI immunostaining (G). Green pixel intensity profiles of individual wild type (I) and Tlc/Tlc (J) stereocilia were obtained from images acquired at the same settings of the confocal microscope. Y axis, green pixel intensities on grey scale from 0 to 256; X, stereocilium length measured from stereocilium tip toward stereocilium base. Scale bars: A–H–5 µm.