Autoradiogram showing results of irradiation of DNA-1/DNA-2, LLP, and condensed plasmid. Numbered arrows on the right indicate the six GG steps of these DNA oligomers. The first five lanes correspond to the dark control, 10 and 20 min of irradiation of the oligomer duplex DNA-1/DNA-2, mixed with 75 μM spermidine and DNA-1/DNA-2, respectively. The next three lanes correspond to 20, 10, and 5 min of irradiation of the LLP, and the last three lanes to that of 20, 10, and 5 min of irradiation of the ligated condensed plasmid, respectively.