Animals often must decide whether or not to consume a diet that contains competing attractive and aversive compounds. Here, using the fruit fly, Drosophila melanogaster, we describe a mechanism that influences this decision. Addition of bitter compounds to sucrose suppressed feeding behavior, and this inhibition depended on an odorant-binding protein (OBP) termed OBP49a. In wild-type flies, bitter compounds suppressed sucrose-induced action potentials, and the inhibition was impaired in Obp49a mutants. However, loss of OBP49a did not affect action potentials in sugar- or bitter-activated gustatory receptor neurons (GRNs) when the GRNs were presented with just one type of tastant. OBP49a was expressed in accessory cells and acted non-cell-autonomously to attenuate nerve firings in sugar-activated GRNs when bitter compounds were combined with sucrose. These findings demonstrate an unexpected role for an OBP in taste andidentify a molecular player involved in the integration of opposing attractive and aversive gustatory inputs
Bibliographical noteFunding Information:
We thank FlyBase, the Bloomington Stock Center and Drs. K. Scott, L. Vosshall, J.W. Posakony, and Y.D. Chung for fly stocks, and Dr. C.Y. Park and Mr. J. Song at the Surface Plasmon Resonance Facility, UNIST, for technical help. The tubulin monoclonal antibody developed by Drs. J. Frankel and E.M. Nelsen was obtained from the Developmental Studies Hybridoma Bank developed under the auspices of the NICHD and maintained by the Department of Biology, University of Iowa (Iowa City, IA). This work was supported by a grant to C.M. from the NIDCD (DC007864) and by grants to S.J.M. from the Converging Research Center Program funded by the Ministry of Education, Science, and Technology (2012K001350) and from the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education, Science, and Technology (2009-0075341 and 2012R1A1A1012081).
ASJC Scopus subject areas
- General Neuroscience