Tex15 is required for vomeronasal sensory neuron diversity and male pheromone detection

The mouse vomeronasal organ (VNO) detects pheromones, which provide vital information needed to find a mate, detect predators, or alert to the presence of an intruder. Within the VNO, pheromones are sensed by two families of G-protein Coupled Receptors (GPCRs) the type 1 and type 2 vomeronasal receptors (V1Rs and V2Rs). However, little is known about the regulatory mechanisms that control the expression of V1R and V2R by vomeronasal sensory neurons (VSNs). Here we show that VSN precursors transiently express Testes-expressed gene 15 (Tex15), which in the germline is required to repress the expression of transposable elements during spermatogenesis. We find that the absence of Tex15 results in a dysregulated VR choice for V1Rs and A, B, and D family V2Rs, which manifest as a less diverse repertoire of VR expressing cells and includes a dramatic reduction in the expression of specific receptors that have been tied to intermale aggression. Accordingly, Tex15 knockout mice exhibit lowered activation in the Accessory Olfactory Bulb (AOB) after exposure to male odorants, and a loss of stereotyped aggression between male mice. Taken together, these results show that Tex15 plays a critical role in pheromone sensing by ensuring that VSNs express a diverse set of receptor proteins.