Figure 4.

Partially deleted mtDNA repopulates mitochondria faster than full-length mtDNA. Different cell lines (identified in the upper left corner of each panel) harboring various mtDNA forms were treated with 50 ng/ml ethidium bromide for 15 d. After this period the drug was removed, and the cells continue to grow for an additional 30 d. DNA samples were obtained at days 0, 6, 15, 22, 30, and 45. Relative mtDNA levels were determined as described in MATERIALS AND METHODS. Note the fast recovery of mtDNA in cell lines harboring partially deleted mtDNA when compared with cells harboring full-length molecules.