Abstract

Mice, Mus musculus, are a primarily nocturnal species that rely heavily on their olfactory system to detect changes in their environment. Specifically, mice rely on protein pheromones, the Major Urinary Proteins (MUPs), non-volatile molecules that are detected by the vomeronasal organ (VNO). MUPs are synthesized in the liver, excreted in the urine, and serve as genetically encoded pheromones which direct social behaviors such as countermarking, aggression, or mate preference. Mice can also use MUPs as a way to detect sex, status, and identity of the emitting individual. MUP expression is thought to be controlled by a set of hormonal axes consisting of testosterone, growth hormone, and thyroxine. The mouse genome encodes 21 MUPs, yet, each adult male mouse will express a unique set of 4-12 MUPs. The mechanism by which MUPs are chosen for expression is non-random, but not well understood. This study looks to understand how individual MUPs are chosen for expression by utilizing a cell culture model system. The female murine liver cell line Hepa1-6, is being used because it does not endogenously show expression of any MUPs, but previous studies have shown that female mice are capable of producing MUPs at male levels if they are exposed to testosterone. A combination of hormonal and drug treatments consisting of methylation inhibitors and deacetylation inhibitors are being used to induce MUP expression in these cultured cells. Following treatment of cells, they are harvested for RNA isolation, and the resulting cDNA library is examined for MUP expression. So far, the chosen treatment periods and concentrations of drugs and hormones have not been sufficient to induce MUP expression. As such, a working protocol for the induction of MUP expression is yet to be established. The creation of a working protocol will in the future contribute to the greater understanding of gene expression.

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