Figure 3. Truncation analysis of the βIGH3 promoter

A: Truncated 1 Kb promoter-luciferase constructs. The top figure depicts the 1 Kb working template, while the next three depict the 5'-deletion constructs and the lower three depict the 3'-deletion constructs. The size of each construct is indicated by the numbers, which are related to the ATG start codon, designated as +1. B: Luciferase activity of the truncated βIGH3 promoters in A549 cells. High promoter activities were noted in the -646 to -1 and -336 to -1 constructs. Deletion of the proximal flanking sequence of 1 Kb in the -1000 to -646, -1000 to -336, and -1000 to -87 fragments abolished the promoter activity of the 1 Kb construct. The results were expressed as an n-fold increase over the pGL3-Basic vector. Each transfection was tested in triplicates in each experiment and four experiments were performed with each construct. Data from four experiments were pooled for statistical analysis. The error bars represent the standard error.