DNA fragmentation in (A) NG-1 cells and (B) NH-1 cells with IPTG stimulation. (A) Lane 1, MW marker; 2 and 3, wild-type K562 cells; 4 and 5, mock-transfected K562 cells; 6 and 7, NG-1 cells; 2, 4, and 6, without, and 3, 5, and 7, with IPTG for 36 hours. (B) Lane 1, MW marker; 2 and 3, wild-type CMK cells; 4 and 5, mock-transfected CMK cells; 6 and 7, NH-1 cells; 2, 4, and 6, without, and 3, 5, and 7, with IPTG for 36 hours.