title: Increased Spontaneous Otoacoustic Emissions in Mice with a Detached Tectorial Membrane.
abstract: Mutations in genes encoding tectorial membrane (TM) proteins are a significant cause of human hereditary hearing loss (Hildebrand et al. 2011), and several mouse models have been developed to study the functional significance of this accessory structure in the mammalian cochlea. In this study, we use otoacoustic emissions (OAE), signals obtained from the ear canal that provide a measure of cochlear function, to characterize a mouse in which the TM is detached from the spiral limbus due to an absence of otoancorin (Otoa, Lukashkin et al. 2012). Our results demonstrate that spontaneous emissions (SOAE), sounds produced in the cochlea without stimulation, increase dramatically in mice with detached TMs even though their hearing sensitivity is reduced. This behavior is unusual because wild-type (WT) controls are rarely spontaneous emitters. SOAEs in mice lacking Otoa predominate around 7 kHz, which is much lower than in either WT animals when they generate SOAEs or in mutant mice in which the TM protein Ceacam16 is absent (Cheatham et al. 2014). Although both mutants lack Hensen's stripe, loss of this TM feature is only observed in regions coding frequencies greater than ~15 kHz in WT mice so its loss cannot explain the low-frequency, de novo SOAEs observed in mice lacking Otoa. The fact that ~80 % of mice lacking Otoa produce SOAEs even when they generate smaller distortion product OAEs suggests that the active process is still functioning in these mutants but the system(s) involved have become less stable due to alterations in TM structure.
authors.affiliation: The Knowles Hearing Center, Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA. m-cheatham@northwestern.edu.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Cheatham
authors.affiliation: The Knowles Hearing Center, Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA.
authors.forename: Aisha
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: The Knowles Hearing Center, Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Goodyear
authors.affiliation: The Knowles Hearing Center, Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Dallos
authors.affiliation: Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
authors.forename: Guy P
authors.initials: GP
authors.lastname: Richardson
mesh_terms: D000818:Animals; D058851:GPI-Linked Proteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D017084:Otoacoustic Emissions, Spontaneous; D013680:Tectorial Membrane / Q000502:physiology*
chemical_list: D058851:GPI-Linked Proteins; C486746:Otoa protein, mouse
keywords: Hensen’s stripe; active process; cochlea; otoancorin; spontaneous otoacoustic emissions; tectorial membrane