Title

TBX1 is required for normal stria vascularis and semicircular canal development.

Document Type

Article

Publication Date

1-1-2020

Keywords

JMG

JAX Source

Dev Dyn 2020; 457(1):91-103

PMID

31550482

DOI

https://doi.org/10.1016/j.ydbio.2019.09.013

Grant

DC0004301,CA034196

Abstract

Little is known about the role of TBX1 in post-otocyst stages of inner ear development. Here, we report on mice with a missense mutation of Tbx1 that are viable with fully developed but abnormally formed inner ears. Mutant mice are deaf due to an undeveloped stria vascularis and show vestibular dysfunction associated with abnormal semicircular canal formation. We show that TBX1 is expressed in endolymph-producing strial marginal cells and vestibular dark cells of the inner ear and is an upstream regulator of Esrrb, which previously was shown to control the developmental fate of these cells. We also show that TBX1 is expressed in sensory cells of the crista ampullaris, which may relate to the semicircular canal abnormalities observed in mutant mice. Inner ears of mutant embryos have a non-resorbed fusion plate in the posterior semicircular canal and a single ampulla connecting anterior and lateral canals. We hypothesize that the TBX1 missense mutation prevents binding with specific co-regulatory proteins. These findings reveal previously unknown functions of TBX1 during later stages of inner ear development.

Comments

We thank Melissa Berry for helpful comments on the manuscript, Sandra Gray for general mouse husbandry, Leona Gagnon for linkage mapping, and Chantal Longo-Guess for in situ hybridization experiments. We also thank personnel of the Jackson Laboratory’s Scientific Research Services for whole exome sequencing and RNA-Seq analyses.

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