IL-6/dexamethasone/PARP inhibitor-sensitive
cis-element of Reg promoter. Luciferase
activities were expressed relative to the level of luciferase activity
in untreated control cells (no addition), which was assigned a value of
1.0. Values represent mean ± SEM of three to eight independent
transfection experiments. Statistical analyses were performed using
Student's t test. (A) Induction of
Reg/luciferase hybrid gene expression by IL-6,
dexamethasone (Dx), and PARP inhibitors. Luciferase activities were
significantly increased by the addition of IL-6/Dx, IL-6/Dx/NA,
and IL-6/Dx/3AB (P < 0.001).
(B) Localization of IL-6/Dx/nicotinamide
(NA)-responsive region in the Reg promoter. In all of
the constructs except for −70, luciferase activities were
significantly increased by the addition of IL-6/Dx and IL-6/Dx/NA
(P < 0.05). (C) Alignment of
Reg gene promoter regions. Rat (18), mouse (52), and
human (16, 31) Reg I gene promoter regions were aligned.
Nucleotide substitutions in the cis-element are
indicated by underlines. Dots indicate residues that are identical to
the rat promoter, and sequence gaps resulting from optimization of
alignment are indicated by dashes. (D) Site-directed
mutagenesis of the cis-element within the
Reg promoter. In all of the mutants except for −81 M1,
significant increases in luciferase activities by the stimulation of
IL-6/Dx and IL-6/Dx/NA were retained (P <
0.01).