Deafness and retinal degeneration in a novel USH1C knock-in mouse model.
Usher syndrome is the leading cause of combined deaf-blindness, but the molecular mechanisms underlying the auditory and visual impairment are poorly understood. Usher I is characterized by profound congenital hearing loss, vestibular dysfunction, and progressive retinitis pigmentosa beginning in early adolescence. Using the c.216G>A cryptic splice site mutation in Exon 3 of the USH1C gene found in Acadian Usher I patients in Louisiana, we constructed the first mouse model that develops both deafness and retinal degeneration. The same truncated mRNA transcript found in Usher 1C patients is found in the cochleae and retinas of these knock-in mice. Absent auditory-evoked brainstem responses indicated that the mutant mice are deaf at 1 month of age. Cochlear histology showed disorganized hair cell rows, abnormal bundles, and loss of both inner and outer hair cells in the middle turns and at the base. Retinal dysfunction as evident by an abnormal electroretinogram was seen as early as 1 month of age, with progressive loss of rod photoreceptors between 6 and 12 months of age. This knock-in mouse reproduces the dual sensory loss of human Usher I, providing a novel resource to study the disease mechanism and the development of therapies.
Lentz
Jennifer J
JJ
Department of Genetics, LSU Health Sciences Center, New Orleans, Louisiana, USA. jlentz@lsuhsc.edu
Gordon
William C
WC
Farris
Hamilton E
HE
MacDonald
Glen H
GH
Cunningham
Dale E
DE
Robbins
Carol A
CA
Tempel
Bruce L
BL
Bazan
Nicolas G
NG
Rubel
Edwin W
EW
Oesterle
Elizabeth C
EC
Keats
Bronya J
BJ
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism; D000375:Aging; D000818:Animals; D018797:Cell Cycle Proteins; D003051:Cochlea / Q000473:pathology / Q000503:physiopathology / Q000648:ultrastructure; D003598:Cytoskeletal Proteins; D003638:Deafness / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D004596:Electroretinography; D016057:Evoked Potentials, Auditory, Brain Stem; D005091:Exons; D055879:Gene Knock-In Techniques; D006198:Hair Cells, Auditory / Q000473:pathology / Q000502:physiology; D008145:Louisiana; D051379:Mice; D008822:Mice, Transgenic; D020125:Mutation, Missense; D022821:RNA Splice Sites; D012333:RNA, Messenger / Q000378:metabolism; D012160:Retina / Q000473:pathology / Q000503:physiopathology; D012162:Retinal Degeneration / Q000473:pathology / Q000503:physiopathology*; D017948:Retinal Rod Photoreceptor Cells / Q000473:pathology / Q000502:physiology; D052245:Usher Syndromes / Q000473:pathology / Q000503:physiopathology*
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D022821:RNA Splice Sites; D012333:RNA, Messenger; C118970:USH1C protein, human