Skip to main content
. 2012 Mar 6;109(12):4473–4478. doi: 10.1073/pnas.1101003109

Fig. 1.

Fig. 1.

Structure of the SO. (A) Tangential section from a type I hair cell EM tomogram showing the structure, periodicity, and location of the SO immediately subjacent to the calyx membrane. (Inset) Thick (numbered) and thin (arrowhead) filament bundles are composed of several thinner, spiral-bundled filaments (e.g., 1–4), measuring ∼10 nm and ∼6 nm, respectively. Note also the cross filaments (small arrows), which EM immunogold studies indicate are likely spectrin (Fig. 5 B and C, and Insets). (Scale bar, 0.2 μm.) (B) Cross-section through the neck of a type I cell showing radial distribution of thick (arrows) and thin (arrowheads) SO filament bundles. They extend from the hair cell membrane to a depth of ∼130 nm into the cell. (Scale bar, 0.2 μm.) (C and D) Apical insertion of a thick SO filament bundle (arrows) adjacent to the kinocilium. The site of insertion is a dimpled area (arrowhead) between the kinocilium and nearby SRs. (D) A SO filament bundle angles downward (arrows), approaching the cell membrane and continuing into the neck of the type I cell. (Scale bar, 0.5 μm; also applies to C.) (E and F) Details of hair-cell neck region in cell 2, obtained with SLICER mode in IMOD. (E) Thick filament bundles of the SO merge together (arrowheads). (Scale bar, 1 μm.) (F) Higher magnification of the area enclosed in the box in E shows possible connections (arrows) between thick filament bundles of the SO and the calyx membrane bridging the intercellular cleft (dashed white lines show locations of hair-cell and calyx membranes). (Scale bar, 0.25 μm.). Cal, calyx; CP, cuticular plate; M, mitochondria.