Figure 3.

Dependence on mitoxantrone concentration of transcriptional blockage. (A) The 512 bp DNA fragment was reacted with mitoxantrone (0–50 µM) and 5 mM formaldehyde in transcription buffer for 2 h at 37°C. The DNA was then ethanol precipitated, resuspended in transcription reaction mix prior to initiation and transcription elongation at 37°C for 5 min. Lane C is a control lacking formaldehyde and other controls are as stated in Figure 1A. (B) Quantitation of increase in transcriptional blockage from (A). The percentage of block 4 (44mer) as a fraction of the entire lane is shown as a function of mitoxantrone concentration. (C) Reduction in percent of full-length transcript from (A) with increasing mitoxantrone concentration.