Sharpened cochlear tuning in a mouse with a genetically modified tectorial membrane.
Frequency tuning in the cochlea is determined by the passive mechanical properties of the basilar membrane and active feedback from the outer hair cells, sensory-effector cells that detect and amplify sound-induced basilar membrane motions. The sensory hair bundles of the outer hair cells are imbedded in the tectorial membrane, a sheet of extracellular matrix that overlies the cochlea's sensory epithelium. The tectorial membrane contains radially organized collagen fibrils that are imbedded in an unusual striated-sheet matrix formed by two glycoproteins, alpha-tectorin (Tecta) and beta-tectorin (Tectb). In Tectb(-/-) mice the structure of the striated-sheet matrix is disrupted. Although these mice have a low-frequency hearing loss, basilar-membrane and neural tuning are both significantly enhanced in the high-frequency regions of the cochlea, with little loss in sensitivity. These findings can be attributed to a reduction in the acting mass of the tectorial membrane and reveal a new function for this structure in controlling interactions along the cochlea.
Russell
Ian J
IJ
School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK. I.J.Russell@sussex.ac.uk
Legan
P Kevin
PK
Lukashkina
Victoria A
VA
Lukashkin
Andrei N
AN
Goodyear
Richard J
RJ
Richardson
Guy P
GP
D000818:Animals; D001489:Basilar Membrane / Q000002:abnormalities / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D002678:Chimera; D003051:Cochlea / Q000002:abnormalities* / Q000378:metabolism / Q000648:ultrastructure; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics; D058851:GPI-Linked Proteins; D018072:Hair Cells, Auditory, Outer / Q000166:cytology / Q000378:metabolism; D006309:Hearing / Q000235:genetics*; D006319:Hearing Loss, Sensorineural / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D008562:Membrane Glycoproteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D010898:Pitch Perception; D013680:Tectorial Membrane / Q000002:abnormalities* / Q000378:metabolism / Q000648:ultrastructure
D016326:Extracellular Matrix Proteins; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C105350:Tecta protein, mouse; C512625:beta-tectorin, mouse; D003094:Collagen