Presynaptic Nrxn3 is essential for ribbon-synapse assembly in hair cells

Hair cells of the inner ear rely on specialized ribbon synapses to transmit sensory information to the central nervous system. The molecules required to assemble these synapses are not fully understood. We show that Nrxn3, a presynaptic adhesion molecule, is critical for ribbon-synapse assembly in hair cells. In both mouse and zebrafish models, loss of Nrxn3 results in significantly fewer intact ribbon synapses. In zebrafish we demonstrate that a 60% loss of synapses in