LM-PCR analysis of Z-DNA-induced DSBs. LM-PCR products were subjected to agarose gel electrophoresis and visualized by ethidium bromide staining. Lane 1, pUCG(14) prepared from DH5α cells; lane 2, pUCON replicated in COS-7 cells for 48 h; lanes 3–6, pUCG(14) replicated in COS-7 cells for 4, 8, 24, and 48 h, respectively. Sizes of detected bands are listed on the right.