1INRA, Unité de Phytopharmacie et Médiateurs Chimiques, Route de St Cyr, 78026 Versailles Cedex, France.
2Phérosynthèse, "Le Rieu Neuf", 84490 Saint Saturnin d'Apt, France.
In Mammals, chemical communication is a crucial part of social life. Pheromones are the most specific chemical messages. Odor perception and recognition seem to be mediated, at the peripheral level, by small soluble odorant-binding proteins which are very abondant in the nasal mucus. Here we report the characterisation of two new pheromone-binding proteins in Sheep Ovis aries and Pig Sus scrofa using a binding assay with olfactory mucosa/vomeronasal organ and three common components of the Pig and Sheep Appeasing Pheromone recently identified. In Sheep, positive binding was obtained with olfactory mucosa whereas in Pig it was obtained with vomeronasal extracts. We show that the coding of pheromones is then ensured by two distinct olfactory pathways according to the species: the main olfactory system in Sheep, and the accessory olfactory system in Pig. The proteins that bind the pheromonal components were N-terminal sequenced. Both proteins show no homologies with previously described OBP. Their molecular cloning is in progress in order to get the total sequences and to study the distribution of their expression in the different olfactory organs.