The shaker-2 mouse mutation, the homolog of human DFNB3, causes deafness and circling behavior. A bacterial artificial chromosome (BAC) transgene from the shaker-2 critical region corrected the vestibular defects, deafness, and inner ear morphology of shaker-2 mice. An unconventional myosin gene, Myo15, was discovered by DNA sequencing of this BAC. Shaker-2 mice were found to have an amino acid substitution at a highly conserved position within the motor domain of this myosin. Auditory hair cells of shaker-2 mice have very short stereocilia and a long actin-containing protrusion extending from their basal end. This histopathology suggests that Myo15 is necessary for actin organization in the hair cells of the cochlea.
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http://dx.doi.org/10.1126/science.280.5368.1444 | DOI Listing |
J Assoc Res Otolaryngol
April 2020
Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA.
Mammalian hair cells develop their mechanosensory bundles through consecutive phases of stereocilia elongation, thickening, and retraction of supernumerary stereocilia. Many molecules involved in stereocilia elongation have been identified, including myosin-XVa. Significantly less is known about molecular mechanisms of stereocilia thickening and retraction.
View Article and Find Full Text PDFHear Res
January 2017
Hearing Research Unit, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia.
Studies of congenital and early-onset deafness have demonstrated that an absence of peripheral sound-evoked activity in the auditory nerve causes pathological changes in central auditory structures. The aim of this study was to establish whether progressive acquired hearing loss could lead to similar brain changes that would degrade the precision of signal transmission. We used complementary physiologic hearing tests and microscopic techniques to study the combined effect of both magnitude and duration of hearing loss on one of the first auditory synapses in the brain, the endbulb of Held (EB), along with its bushy cell (BC) target in the anteroventral cochlear nucleus.
View Article and Find Full Text PDFHear Res
January 2017
Hearing Research Unit, Neuroscience Division, Garvan Institute of Medical Research, Darlinghurst, NSW, 2010, Australia; School of Medical Sciences, Faculty of Medicine, UNSW Australia, Sydney, NSW, 2052, Australia; Department of Otolaryngology, Head, Neck & Skull Base Surgery, St Vincent's Hospital, Sydney, NSW, 2010, Australia.
Auditory efferent neurons reside in the brain and innervate the sensory hair cells of the cochlea to modulate incoming acoustic signals. Two groups of efferents have been described in mouse and this report will focus on the medial olivocochlear (MOC) system. Electrophysiological data suggest the MOC efferents function in selective listening by differentially attenuating auditory nerve fiber activity in quiet and noisy conditions.
View Article and Find Full Text PDFHum Mutat
October 2016
Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, 20892.
Deafness in humans is a common neurosensory disorder and is genetically heterogeneous. Across diverse ethnic groups, mutations of MYO15A at the DFNB3 locus appear to be the third or fourth most common cause of autosomal-recessive, nonsyndromic deafness. In 49 of the 67 exons of MYO15A, there are currently 192 recessive mutations identified, including 14 novel mutations reported here.
View Article and Find Full Text PDFIn Vivo
January 2013
Institute of DNA Sciences, 261-2 Yamate-cho, Naka-ku, Yokohama, 231-0862, Japan.
Background: We have established a mouse model of spontaneous deafness by sib-inbreeding over 10 years. The mouse was designated as kuru(2) and has been previously reported in this Journal.
Materials And Methods: In order to identify the genetic abnormality, the mouse was back-crossed to Mus musculus castaneus (CAST), and myosine 15 or myoXV on chromosome 11 was assumed to be the responsive gene.
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