Fig. 3. Incubation of TnsCD-bound attTn7 target DNA with TnsB decreases subsequent transposition. TnsB^wt was added to the reactions in lanes 1–5 and TnsB^V689M was added to the reactions in lanes 6–10. Bands are labeled as in Figure 2B. The bands above the donor result from a double-strand break at either Tn7R or Tn7L that was ‘single end joined’ to the target DNA (DSB-R/SEJ and DSB-L/SEJ) (Bainton et al., 1993).