Regulation of Gene Expression of Mouse D-Amino Acid Oxidase.

D-amino acid oxidase (DAO) catalyzes oxidative deamination of D-amino acids, producing 2-oxo acids, hydrogen peroxide and ammonia. In mammals, DAO is essential for metabolizing both endogenous and exogenous D-amino acids. Our previous studies on human DAO identified two promoter regions (P1 and P2), a negative regulatory element in intron 1, and several transcription factor binding sites. In this study, we investigated the regulatory mechanism of mouse DAO gene expression to compare with the human system. Poly (I:C) or Interleukin-1βtreatment induced DAO expression by 1.8-2.0 folds in the mouse brain, cerebellum and cerebral cortex. To determine the promoter activity in the upstream region of initiation site, we constructed plasmids containing mouse DAO gene fragments inserted into pGL4 [luc2P/Hygro] vector and assessed luciferase activity in LLC-PK1 cells. We analyzed a series of deletion constructs, revealing promoter activity in all tested fragments. The highest promoter activity was detected in the -333/-87 subregion, with residual activities in the -87/+111 region. Bioinformatics analysis identified transcription factors, including NEUR, EGRF, ZF07, ZF11, KLFS, SP1F and ZF02, which bind to both the human and mouse DAO genes at conserved positions, suggesting their critical role in regulating DAO promoter activity.