Function of Bidirectional Sensitivity in the Otolith Organs Established by Transcription Factor Emx2

Overview

Journal Nat Commun

Specialty Biology

Date 2022 Oct 24

PMID 36280667

Authors

Young Rae Ji

Yosuke Tona

Talah Wafa

Matthew E Christman

Edward D Tourney

Tao Jiang

Sho Ohta

Hui Cheng

Tracy Fitzgerald

Bernd Fritzsch

Sherri M Jones

Kathleen E Cullen

Doris K Wu

Affiliations

Soon will be listed here.

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.

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