Figure 4.

Deletion mutants of the CMV-IE promoter are susceptible to the inhibition of the reporter gene expression by single 8-oxoG. (A) List of vectors containing the modified CMV_1111 promoter or its truncated versions together with the map of the introduced deletions. Batons show the canonical CRE sequences. (B) Fluorescence distribution plots and quantification of EGFP expression in HeLa cells 24 h post-transfection with the specified promoter constructs without artificially introduced base modifications. (C) Overlaid EGFP fluorescence distribution plots of cells transfected with vectors containing synthetic DNA strand with one 8-oxoG (amber) and those containing the respective unmodified oligonucleotide (blue). (D) Impact of single 8-oxoG on the gene expression as a function of promoter strength. Data of three independent experiments and the best-fit linear regression lines. EGFP expression was measured at 6 and 24 h post-transfection and calculated relative to expression of the matched construct without 8-oxoG.