FIGURE 5.

Manipulation of NFκB p50 and C/EBPβ expression reciprocally affects reporter gene expression. A, the 2,461-bp let-7i promoter increased transcription over 12-fold compared with the pGL4.22 empty vector. Overexpression (oe) of p50 significantly decreased luciferase expression over 25%, whereas C/EBPβ overexpression diminished luciferase expression over 75%. Concurrent overexpression of these transcription factors synergistically represses luciferase expression from this promoter. B, same plasmid construct was used to demonstrate that RNA-mediated silencing of these transcription factors reciprocally affected luciferase expression driven from this promoter. Furthermore, siRNA-induced repression of p50 or C/EBPβ inhibited microbial-induced reduction of luciferase driven by the let-7i promoter. Data are represented as mean ± S.E. from three separate experiments with at least n = 4 for each experiment. *, p < 0.05 between comparisons indicated, using ANOVA.