Abstract
Mental disorders, such as depression and abnormal behaviors, are increasingly important social and medical issues in 21st century. Nutrients, including tryptophan (Trp) and its metabolites, are thought to be important for healthy mental development. Tryptophan 2,3-dioxygenase (TDO) is one first and rate-limiting enzyme for Trp metabolic pathway, and plays an important role in physiological regulation of systemic Trp metabolism, brain serotonin synthesis, and mood. Here, we analyzed single nucleotide polymorphisms (SNPs) in mouse tdo gene between C57BL/6J mice and BALB/c mice, which exhibits different phenotypes with behavioral analyses. Three SNPs in mouse tdo gene were identified between each strain, and one of three, G87T SNPs, was missense mutation, V18L, in the highly conserved in various species. However, since the expression levels of hepatic TDO protein and TDO enzyme activity were not different between each strain, this mutation might little effect on physiological TDO function in the liver. Further analyses of the association genetic and functional TDO modification with individual character in selective bleeding and mental disorders will be need in companion animal.
