Deletion analysis of the human TMP21 gene promoter. (A) Schematic diagram of the TMP21 promoter constructs consisting of the 5' flanking region with serial deletions cloned into the pGL3-basic vector. Arrow shows the direction of transcription. The numbers represent the end points of each construct. The deletion plasmids were confirmed by sequencing and restriction enzyme digestion. (B) The plasmid constructs were co-transfected with pRLuc into HEK293 and SH-SY5Y cells by Lipofectamine 2000R. After 48 hour transfections the cells were harvested and luciferase activity was measured with a luminometer and expressed in Relative Luciferase Units (RLU). Renilla luciferase activity was used to normalize for transfection efficiency. The values represent means ± SEM. *, P < 0.001 by analysis of variance with the post hoc Newman-Keuls test.