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. The background abnormality was identified by gene sequencing.
Results: Deletion of 2446 base pairs occurred in the mouse (from 28795 to 31241 in the complete sequence of the Mus musculus unconventional myosin-15 gene; NCBI accession: AF144093).
Discussion: The myosin ATP-binding site is present in the deleted area. Considering the function that the affected area regulates and previous reports, hearing loss of the examined mouse is attributable to the abnormality of the myoXV gene and this mouse might be another type of shaker-2 deaf mouse.
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Hear 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 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.
J Assoc Res Otolaryngol
September 2006
Kresge Hearing Research Institute, Department of Otolaryngology/Head-Neck Surgery, University of Michigan Medical School, Ann Arbor, MI 48109-0648, USA.
The vertebrate cochlea is a complex organ optimized for sound transduction. Auditory hair cells, with their precisely arranged stereocilia bundles, transduce sound waves to electrical signals that are transmitted to the brain. Mutations in the unconventional myosin XV cause deafness in both human DFNB3 families and in shaker 2 (sh2) mice as a result of defects in stereocilia.
View Article and Find Full Text PDFNat Cell Biol
February 2005
Section on Human Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, MD 20850, USA.
Stereocilia are microvilli-derived mechanosensory organelles that are arranged in rows of graded heights on the apical surface of inner-ear hair cells. The 'staircase'-like architecture of stereocilia bundles is necessary to detect sound and head movement, and is achieved through differential elongation of the actin core of each stereocilium to a predetermined length. Abnormally short stereocilia bundles that have a diminished staircase are characteristic of the shaker 2 (Myo15a(sh2)) and whirler (Whrn(wi)) strains of deaf mice.
View Article and Find Full Text PDFJ Neurocytol
March 2003
Center for Hearing Sciences, Departments of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
It is well established that manipulation of the sensory environment can significantly alter central auditory system development. For example, congenitally deaf white cats exhibit synaptic alterations in the cochlear nucleus distinct from age-matched, normal hearing controls. The large, axosomatic endings of auditory nerve fibers, called endbulbs of Held, display reduced size and branching, loss of synaptic vesicles, and a hypertrophy of the associated postsynaptic densities on the target spherical bushy cells.
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