TY - JOUR TI - Directional selectivity of afferent neurons in zebrafish neuromasts is regulated by Emx2 in presynaptic hair cells AU - Ji, Young Rae AU - Warrier, Sunita AU - Jiang, Tao AU - Wu, Doris K AU - Kindt, Katie S A2 - Bronner, Marianne VL - 7 PY - 2018 DA - 2018/04/19 SP - e35796 C1 - eLife 2018;7:e35796 DO - 10.7554/eLife.35796 UR - https://doi.org/10.7554/eLife.35796 AB - The orientation of hair bundles on top of sensory hair cells (HCs) in neuromasts of the lateral line system allows fish to detect direction of water flow. Each neuromast shows hair bundles arranged in two opposing directions and each afferent neuron innervates only HCs of the same orientation. Previously, we showed that this opposition is established by expression of Emx2 in half of the HCs, where it mediates hair bundle reversal (Jiang et al., 2017). Here, we show that Emx2 also regulates neuronal selection: afferent neurons innervate either Emx2-positive or negative HCs. In emx2 knockout and gain-of-function neuromasts, all HCs are unidirectional and the innervation patterns and physiological responses of the afferent neurons are dependent on the presence or absence of Emx2. Our results indicate that Emx2 mediates the directional selectivity of neuromasts by two distinct processes: regulating hair bundle orientation in HCs and selecting afferent neuronal targets. KW - hair bundle polarity KW - Vangl2 KW - axonal guidance KW - afferent neuron KW - planar cell polarity KW - neuronal selection JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -