Fig. 8

G-quadruplex ligands modulate promoter activity of KSHV and HCMV miRNAs for wild-type contructs but not mutant constructs. Bar graphs showing promoter activity as measured by firefly luciferase levels normalized with renilla luciferase levels (transfection control). The relative luciferase units (RLU) values of the reporter constructs in the presence of the ligand were nomarlized to that of the respective reporter constructs in the absence of the ligand. (a) The addition of TMPyP4 (50 μM) was associated with significant reduction in promoter activity of Wt-KSHV-GQ promoter, however (b) the addition of PDS (10 μM), led to a significant increase in promoter activity of the Wt-KSHV-GQ promoter. (c) Conversely, TMPyP4 (50 μM) significantly enhanced Wt-HCMV-GQ promoter activity while (d) PDS (10 μM) inhibited the Wt-HCMV-GQ promoter activity. It is clear from panel (a) through (d) that neither TMPyP4 nor PDS alter the promoter activity the mutant reporter constructs i.e. Mut-KSHV-GQ and Mut-HCMV-GQ; both containing G-quadruplex disrupting mutations. These findings ascertain a role for DNA secondary strucutures in modulating promoter activity of KSHV and HCMV miRNAs. Experiments were performed in triplicates and mean values ±SD were plotted