Meeting Abstract

S1.11  Sunday, Jan. 4  Auditory transduction in Drosophila GOPFERT, M. C.; Univ. of Gottingen, Germany m.gopfert@uni-koeln.de

Hearing is a multi-step process that starts with the conversion of acoustic energy into mechanical vibrations (stimulus reception), the funnelling of these vibrations to dedicated mechanosensory cells and molecules (coupling), the transformation of the vibrations into electrical currents (mechano-electrical transduction), and the subsequent conversion of these currents into spike-trains that are forwarded to the CNS (encoding). We report that the molecular mechanism that brings about mechano-electrical transduction governs the macroscopic performance of a whole ear. In Drosophila, hearing is mediated by ca. 500 primary mechanosensory neurons that connect to an external sound receiver formed by the distal part of the antenna. We found that this antennal sound receiver displays all the mechanical key characteristics that have been reported for the sensory hair bundles of vertebrate hair cells, including signatures of transducer gating, transducer adaptation, and active amplification. We further found that, with minor modifications, a transduction model as proposed for vertebrate hair cells explains all these hair-bundle-like properties of the flys sound receiver as well as properties of electrical compound responses in the auditory afferent nerve. As judged from our analysis, hearing in Drosophila relies on directly gated, fully adapting transduction channels, whereby the interplay between these channels and associated adaptation motors actively shapes auditory system performance. Knocking down putative transduction molecules in the fly’s auditory mechanosensory cells is shown to profoundly alter the mechanical properties of the ear.