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Chondrocyte‐specific Smad4 gene conditional knockout results in hearing loss and inner ear malformation in mice
Author(s) -
Yang ShiMing,
Hou ZhaoHui,
Yang Guan,
Zhang JiShuai,
Hu YinYan,
Sun JianHe,
Guo WeiWei,
He David z. z.,
Han DongYi,
Young WieYen,
Yang Xiao
Publication year - 2009
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.22014
Subject(s) - inner ear , biology , conditional gene knockout , stereocilia (inner ear) , embryonic stem cell , cochlea , basilar membrane , knockout mouse , microbiology and biotechnology , zebrafish , hair cell , anatomy , hearing loss , sensorineural hearing loss , genetics , gene , phenotype , audiology , medicine
Smad4 is the central intracellular mediator of transforming growth factor‐β (TGF‐β) signaling, which plays crucial roles in tissue regeneration, cell differentiation, embryonic development, and regulation of the immune system. Conventional Smad4 gene knockout results in embryonic lethality, precluding its use in studies of the role of Smad4 in inner ear development. We used chondrocyte‐specific Smad4 knockout mice ( Smad4 Co/Co ) to investigate the function of Smad4 in inner ear development. Smad4 Co/Co mice were characterized by a smaller cochlear volume, bone malformation, and abnormalities of the osseous spiral lamina and basilar membrane. The development of the hair cells was also abnormal, as evidenced by the disorganized stereocilia and reduced density of the neuronal processes beneath the hair cells. Auditory function tests revealed the homozygous Smad4 Co/Co mice suffered from severe sensorineural hearing loss. Our results suggest that Smad4 is required for inner ear development and normal auditory function in mammals. Developmental Dynamics, 2009. © 2009 Wiley‐Liss, Inc.