The original plasmid, plasmid with S1 nuclease digestion, plasmid with T7 endonuclease digestion, and plasmid with restriction enzyme digestion that cuts the plasmid only once were subjected to agarose gel electrophoresis in this order. Lanes 1–4, psPATRR11; lanes 5–8, pΔPATRR11; lanes 9–12, TA cloning vector. The arrows indicate the position of the linear form of psPATRR11 (a), pΔPATRR11 (b), and TA cloning vector (c). S1, S1 nuclease; T7, T7 endonuclease; RE, restriction enzyme.