Gene expression profiling of the olfactory tissues from sex-separated and sex-combined female and male mice

We sought to investigate the scope of cellular and molecular changes within a mouse’s olfactory system as a function of its exposure to odors emitted from members of the opposite sex. To this end, we housed mice either separated from members of the opposite sex (sex-separated) or together with members of the opposite sex (sex-combined) until six months of age and then profiled transcript levels within the main olfactory epithelium (MOE), vomeronasal organ (VNO), and olfactory bulb (OB) of the mice via RNA-seq. For each tissue type, we then analyzed gene expression differences between sex-separated males and sex-separated females (SM v SF), sex-combined males and sex-combined females (CM v CF), sex-separated females and sex-combined females (SF v CF), and sex-separated males and sex-combined males (SM v CM). Within both the MOE and VNO, we observed significantly more numerous gene expression differences between males and females when mice were sex-separated as compared to sex-combined. Chemoreceptors were highly enriched among the genes differentially expressed between males and females in sex-separated conditions, and these expression differences were found to reflect differences in the abundance of the corresponding sensory neurons. For each combination of tissue (MOE, VNO, OB), sex (F, M), and condition (sex-separated [S], sex-combined [C]), we generated three biological replicate samples of RNA, each of which contained equal quantities of RNA from two different mice. This resulted in a total of 36 samples.