title: Transcription factor Emx2 controls stereociliary bundle orientation of sensory hair cells.
abstract: The asymmetric location of stereociliary bundle (hair bundle) on the apical surface of mechanosensory hair cells (HCs) dictates the direction in which a given HC can respond to cues such as sound, head movements, and water pressure. Notably, vestibular sensory organs of the inner ear, the maculae, exhibit a line of polarity reversal (LPR) across which, hair bundles are polarized in a mirror-image pattern. Similarly, HCs in neuromasts of the zebrafish lateral line system are generated as pairs, and two sibling HCs develop opposite hair bundle orientations. Within these sensory organs, expression of the transcription factor Emx2 is restricted to only one side of the LPR in the maculae or one of the two sibling HCs in neuromasts. Emx2 mediates hair bundle polarity reversal in these restricted subsets of HCs and generates the mirror-image pattern of the sensory organs. Downstream effectors of Emx2 control bundle polarity cell-autonomously via heterotrimeric G proteins.
authors.affiliation: Program in Neuroscience and Cognitive Science, University of Maryland, College Park, United States.|Laboratory of Molecular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States.
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Section on Sensory Cell Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States.
authors.forename: Katie
authors.identifier: 0000-0002-1065-8215
authors.initials: K
authors.lastname: Kindt
authors.affiliation: Laboratory of Molecular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States.
authors.forename: Doris K
authors.identifier: 0000-0002-1400-3558
authors.initials: DK
authors.lastname: Wu
mesh_terms: D000818:Animals; D007758:Ear, Inner / Q000196:embryology*; D018069:Hair Cells, Vestibular / Q000502:physiology*; D018398:Homeodomain Proteins / Q000378:metabolism*; D038081:Organogenesis; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D015027:Zebrafish / Q000196:embryology*; D000099260:Empty Spiracles Homeobox Proteins
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors; D000099260:Empty Spiracles Homeobox Proteins
keywords: chicken; developmental biology; inner ear; line of polarity reversal; mouse; neuromast; neuroscience; planar cell polarity; saccule; stem cells; utricle; zebrafish