A deafness mutation isolates a second role for the tectorial membrane in hearing.
Alpha-tectorin (encoded by Tecta) is a component of the tectorial membrane, an extracellular matrix of the cochlea. In humans, the Y1870C missense mutation in TECTA causes a 50- to 80-dB hearing loss. In transgenic mice with the Y1870C mutation in Tecta, the tectorial membrane's matrix structure is disrupted, and its adhesion zone is reduced in thickness. These abnormalities do not seriously influence the tectorial membrane's known role in ensuring that cochlear feedback is optimal, because the sensitivity and frequency tuning of the mechanical responses of the cochlea are little changed. However, neural thresholds are elevated, neural tuning is broadened, and a sharp decrease in sensitivity is seen at the tip of the neural tuning curve. Thus, using Tecta(Y1870C/+) mice, we have genetically isolated a second major role for the tectorial membrane in hearing: it enables the motion of the basilar membrane to optimally drive the inner hair cells at their best frequency.
School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
P Kevin
PK
Legan
Victoria A
VA
Lukashkina
Richard J
RJ
Goodyear
Andrei N
AN
Lukashkin
Kristien
K
Verhoeven
Guy
G
Van Camp
Ian J
IJ
Russell
Guy P
GP
Richardson
D000161:Acoustic Stimulation; D000200:Action Potentials; D000818:Animals; D003051:Cochlea / Q000503:physiopathology; D003055:Cochlear Microphonic Potentials; D003638:Deafness / Q000235:genetics / Q000503:physiopathology*; D004056:Differential Threshold; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D058851:GPI-Linked Proteins; D006198:Hair Cells, Auditory / Q000473:pathology; D018072:Hair Cells, Auditory, Outer; D006309:Hearing / Q000502:physiology*; D040542:Mechanotransduction, Cellular; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D020125:Mutation, Missense; D017084:Otoacoustic Emissions, Spontaneous; D012405:Round Window, Ear / Q000503:physiopathology; D013680:Tectorial Membrane / Q000473:pathology / Q000502:physiology*
D016326:Extracellular Matrix Proteins; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; C105350:Tecta protein, mouse