Helical structure of hair cell stereocilia tip links in the chinchilla cochlea.
Outer-hair-cell stereocilia tip-link structure in the chinchilla cochlea was studied by transmission electron microscopy using tannic acid and Ruthenium red/ Alcian blue histochemical procedures. Tannic acid and Ruthenium red/Alcian blue treatments showed the tip link as a compact strand of filaments 9-12 nm thick. Fourier analysis of tip-link images showed that the strand is a three-start helical bundle of fine, coiled filaments which had an axial period of 22.5+/-1.5 nm. Each of three coiled filaments in the strand showed globular structures, 4.3+/-0.3 nm in diameter. The globular structures may correspond to individual protein subunits or they may be repeating identical domains of one polypeptide. The three filaments of the helical array may provide a rigidity to the tip link during stereocilia deflections. Alternatively, changes in the subunit or domain structure of each filament may result in a lengthening or shortening of the tip-link strand.
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Department of Otolaryngology, University of Minnesota, Minneapolis 55455, USA.
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D000818:Animals; D002682:Chinchilla / Q000033:anatomy & histology*; D002923:Cilia / Q000648:ultrastructure*; D003051:Cochlea / Q000648:ultrastructure*; D005583:Fourier Analysis; D006198:Hair Cells, Auditory / Q000648:ultrastructure*; D006651:Histocytochemistry; D007091:Image Processing, Computer-Assisted; D008854:Microscopy, Electron