Publication Date:
2015-11-21
Description:
The DFNB31 gene plays an indispensable role in the cochlea and retina. Mutations in this gene disrupt its various isoforms and lead to non-syndromic deafness, blindness and deaf-blindness. However, the known expression of Dfnb31 , the mouse ortholog of DFNB31 , in vestibular organs and the potential vestibular-deficient phenotype observed in one Dfnb31 mutant mouse ( Dfnb31 wi/wi ) suggest that DFNB31 may also be important for vestibular function. In this study, we find that full-length (FL-) and C-terminal (C-) whirlin isoforms are expressed in the vestibular organs, where their stereociliary localizations are similar to those of developing cochlear inner hair cells. No whirlin is detected in Dfnb31 wi/wi vestibular organs, while only C-whirlin is expressed in Dfnb31 neo/neo vestibular organs. Both FL- and C-whirlin isoforms are required for normal vestibular stereociliary growth, although they may play slightly different roles in the central and peripheral zones of the crista ampullaris. Vestibular sensory-evoked potentials demonstrate severe to profound vestibular deficits in Dfnb31 neo/neo and Dfnb31 wi/wi mice. Swimming and rotarod tests demonstrate that the two Dfnb31 mutants have balance problems, with Dfnb31 wi/wi mice being more affected than Dfnb31 neo/neo mice. Because Dfnb31 wi/wi and Dfnb31 neo/neo mice faithfully recapitulate hearing and vision symptoms in patients, our findings of vestibular dysfunction in these Dfnb31 mutants raise the question of whether DFNB31 -deficient patients may acquire vestibular as well as hearing and vision loss.
Print ISSN:
0964-6906
Electronic ISSN:
1460-2083
Topics:
Biology
,
Medicine
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