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Function of bidirectional sensitivity in the otolith organs established by transcription factor Emx2
Journal article   Open access   Peer reviewed

Function of bidirectional sensitivity in the otolith organs established by transcription factor Emx2

Young Rae Ji, Yosuke Tona, Talah Wafa, Matthew E. Christman, Edward D. Tourney, Tao Jiang, Sho Ohta, Hui Cheng, Tracy Fitzgerald, Bernd Fritzsch, …
Nature communications, Vol.13(1), pp.6330-6330
10/24/2022
DOI: 10.1038/s41467-022-33819-3
url
https://doi.org/10.1038/s41467-022-33819-3View
Published (Version of record) Open Access

Abstract

Otolith organs of the inner ear are innervated by two parallel afferent projections to the brainstem and cerebellum. These innervations were proposed to segregate across the line of polarity reversal (LPR) within each otolith organ, which divides the organ into two regions of hair cells (HC) with opposite stereociliary orientation. The relationship and functional significance of these anatomical features are not known. Here, we show regional expression of Emx2 in otolith organs, which establishes LPR, mediates the neuronal segregation across LPR and constitutes the bidirectional sensitivity function. Conditional knockout (cKO) of Emx2 in HCs lacks LPR. Tmie cKO, in which mechanotransduction was abolished selectively in HCs within the Emx2 expression domain also lacks bidirectional sensitivity. Analyses of both mutants indicate that LPR is specifically required for mice to swim comfortably and to traverse a balance beam efficiently, but LPR is not required for mice to stay on a rotating rod. The inner ear is highly organized, with distinct domains being located across the Line of Polarity Reversal (LPR). Here they show that Emx2 establishes the LPR and bidirectional selectivity of otolith organs, and that loss of the LPR in mice affects swimming and balance.
Inner ear Neuronal development Pattern formation

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