A Fatty Acid Anabolic Pathway in Specialized-Cells Remotely Controls Oocyte Activation in Drosophila

Pheromone-mediated partner recognition is crucial for maintenance of animal species. Here, we discover a metabolic link between pheromone and gamete physiology. In female genital tract, oocyte maturation is arrested at a specific meiotic-phase. Release of this arrest, called oocyte-activation, is triggered by a species-dependent signal. We show in Drosophila melanogaster that oenocytes, which produce the fatty acids (FAs) used as precursors of cuticular hydrocarbons (CHCs), including pheromones, are also essential for oocyte activation. We identified a set of FA-anabolic enzymes required within oenocytes for the synthesis of a particular FA that is not a CHC precursor but controls oocyte activation. Our study thus reveals that two tightly linked FA-anabolic pathways act in parallel, one to produce sexual pheromones, the other to initiate embryonic development. Given that pheromone-deficient Drosophila melanogaster females are highly attractive for males irrespective of their species, this oenocyte function might have evolved to prevent hybrid development.