Anti-Inflammatory Cytokine Interleukin-4 Inhibits Inducible Nitric Oxide Synthase Gene Expression in the Mouse Macrophage Cell Line RAW264.7 through the Repression of Octamer-Dependent Transcription
Figure 3
Deletion analysis of the mouse Nos2 enhancer/promoter region by luciferase reporter assays in RAW264.7 cells. The diagram on the left shows the wild-type (pNOS-996) and deletion constructs of the Nos2 luciferase reporter. The numbers above the enhancer/promoter region refer to the nucleotide positions relative to the transcriptional start site of the mouse Nos2 gene. NF-κB, nuclear factor kappa B; GAS, gamma-IFN activation sequence; ISRE, interferon-stimulated responsive element; NF-IL-6, nuclear factor IL-6; OCT, octamer transcription factor; TATA, TATA-box. RAW264.7 cells were transiently transfected with wild-type or mutant Nos2 luciferase reporter constructs. Twenty-four hours after transfection, the cells were either left untreated (UT) or treated with IL-4 (10 ng/mL) for 30 min prior to stimulation with IFNγ (10 ng/mL) and/or LPS (100 ng/mL) for 8 hours before measurement of the luciferase activity. The relative luciferase activities are shown as percentages of the activity in cells transfected with the wild-type construct (pNOS-996) and stimulated with IFNγ and LPS. Each column and bar represents the mean ± SEM of five independent experiments. The asterisks denote a statistically significant difference compared to the cultures with IL-4 (, Student’s test).
