Figure 8.

A summary of events that occur in MCF7 cells exposed to GC-DNA (pEGFP-rDNA as an example), which harbor genes that can be transcribed. (1)—GC-DNA approaches and interacts with the cell surface. (2)—GC-DNA stimulates a burst of ROS generation at the site of contact with the cell. ROS level is independent of the presence of easily oxidizable motifs. (3)—the easily oxidizable bases of rDNA (or other human easily oxidizable DNA sequences) are oxidized. GC-DNA without an easily oxidizable rDNA insert is oxidized to a lesser degree. (4)—oxidized GC-DNA is transfected into the cell nucleus and can be expressed (EGFP gene in pEGFP-rDNA molecules with intact promoter is expressed). GC-rDNA molecules are accumulated in the nucleolus.