Effect of PFTα on fludarabine-induced transcription of p21^CIP1 and Puma. Cells from patient 4 were incubated in the presence of 100 μM ZVAD. Fludarabine (10 μM) and/or 25 μM PFTα were added as indicated. Cells were fractionated by DDF and analyzed by Western blotting. The nuclear fractions (Fn 3) were run on a separate gel from fractions 1 and 2.