Regulation of TMP21 promoter activity by NFAT and PDTC. Transcriptional activation of the TMP21 promoter is potentiated by NFAT. Empty vector and TMP21 promoter plasmid pTMP-1260+33 or pTMP-120+33 were cotransfected with NFAT expression plasmid pHA-NFAT1 into HEK293 cells (A) or N2a cells (B). Overexpression of NFAT significantly increased pTMP21-1260+33 or promoter activity and had no effect on pTMP-120+33 or control plasmid in both HEK293 and N2a cells. n = 4, * p < 0.0001. (C, D) Inhibition of TMP21 promoter activity by PDTC. TMP21 promoter construct pTMP21-1260+33 and pRluc were cotransfected into HEK293 and N2a cells. After 24 h cells were treated with varying dosages of PDTC for 16 hours (C) or at 100uM for varying times (D). Cells were harvested at the same time for luciferase assay. Renilla luciferase activity was used to normalize for transfection efficiency. The values represent means ± SEM relative to control promoter activity. *, P < 0.001 relative to control by ANOVA with the post hoc Newman-Keuls test.