Ciliated epithelial cells in the kidney detect fluid flow 5, and ciliated receptor neurons in insect bristle receptors, campaniform sensilla and chordotonal organs sense forces associated with touch, air flow, cuticle deformation, gravity and sound 6. elegans) mediate the response to touch 4. Ciliated and non-ciliated sensory neurons in Caenorhabditis elegans ( C. In addition to actin-based mechanoreceptors such as hair cells, vertebrates and invertebrates contain microtubule-based sensory cells. Shearing of adjacent actin-filled stereocilia within the bundle tenses extracellular links and leads to the opening of transduction channels located close to the apical tips of the stereocilia 3. A well-studied example of such a cytoskeletal linkage apparatus is the hair bundle of hair cells, the receptor cells underlying the senses of hearing and balance in the vertebrate inner ear. Mechanosensory cells often contain elaborate cytoskeletal structures that provide a mechanical link from the external stimulus to the receptor module. This signal may function locally within the tissue to regulate cellular motility, growth or differentiation 1 or it may be transmitted to the central nervous system where it can lead to the perception of sound, touch or accelerations 2. Mechanotransduction is the process by which a mechanical force impinging on a cell produces an intracellular signal. Our results establish a catalogue of candidate genes for Drosophila mechanosensation and show that one candidate, DCX-EMAP, is likely to be required for mechanosensory transduction and amplification. Electron microscopy of mutant sensilla reveals loss of electron-dense materials within the microtubule cytoskeleton in the tubular body and ciliary dilation. Adult flies carrying a piggyBac insertion in the DCX-EMAP gene are uncoordinated and deaf and display loss of mechanosensory transduction and amplification. DCX-EMAP localizes to the tubular body in campaniform receptors and to the ciliary dilation in chordotonal mechanoreceptors in Johnston's organ, the fly's auditory organ. In a screen for genes preferentially expressed in Drosophila campaniform mechanoreceptors, we identified DCX-EMAP, a unique member of the EMAP family (echinoderm–microtubule-associated proteins) that contains two doublecortin domains. Ciliated mechanoreceptors possess an elaborate microtubule cytoskeleton that facilitates the coupling of external forces to the transduction apparatus. Mechanoreceptors are sensory cells that transduce mechanical stimuli into electrical signals and mediate the perception of sound, touch and acceleration.
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