Figure 2.

Representative PCR analysis of DSB-induced mutations. PCR was performed on samples of genomic DNA isolated from TFT^R clones recovered from cells after electroporation with pCMV-I-SceI and a HaeIII digest of φX174 DNA. The pair of primers used were positioned 1.5 kb apart and flanked the I-SceI site (Fig. 1A). Shown here is a representative analysis of parental cell line 2 (lane 12) and 10 TFT^R clones derived from cell line 2 (lanes 2–11). Parental cell line 2 generated a 1.5 kb PCR product. Among the 10 TFT^R clones, seven clones (lanes 3–7, 9 and 11) displayed PCR products indistinguishable in size from that of the parent. Two clones (lanes 2 and 10) displayed PCR products clearly larger than that of the parent whereas one failed to produce a PCR product (lane 8). Lane 1 displays a negative control PCR reaction to which no template DNA was added. A total of 132 TFT^R clones isolated from cell lines 2 and 4 were analyzed by PCR in a similar manner. See text for further details.