The implication of OBP28a in <em>Drosophila melanogaster</em> chemosensory perception

National audienceChemoperception is critical for animals to detect nutritive food and avoid toxic compounds. As many other insects, Drosophila melanogaster uses various semiochemicals including pheromones and food volatiles to identify a suitable ecological niche and a mating partner. Chemosensory detection is mostly mediated by olfactory and gustatory systems involving several multigene chemoreceptor families. Volatile and non-volatile chemicals compounds entering into the sensory organ (sensillum) must be solubilized before being transported through the hydrophilic sensillum lymph bathing the chemosensory neurons. Such perireceptor events involve a family of soluble proteins named odorant-binding proteins (OBPs). Whereas the physiological role of OBPs is not clear, a recent study demonstrated that one abundant OBP, OBP28a is not required for odorant transport but acts in buffering changes in the odor environment 1. To clarify the role of OBP28a in the perception of food and pheromonal compounds in D. melanogaster adults, we heterologously produce OBP28a using the yeast Pichia pastoris. OBP28a was purified and its ligand binding properties were investigated using a fluorescent binding assay. We determined the best candidate-ligands and tested the preference to these compounds using two behavioral paradigms. Our current data suggest that OBP28a changes the response of transgenic flies to a potential pheromonal compound. The behavior of flies to several other molecules will be tested in the near future. 1. Larter, N. K., Sun, J. S. & Carlson, J. R. Organization and function of Drosophila odorant binding proteins. eLife 5, 1–22 (2016)