Electrophoretic mobility
shift analysis of the effect of TFOs on the binding of nuclear factors
present in PMA-treated K562 cells to the target region of the c-sis/PDGF-B promoter. Radiolabeled duplex target, the 255 bp promoter fragment isolated from the pUC18promoter,
(30 nM) was preincubated with increasing concentration (1, 5 or
20 µM) of single-stranded TFO1 (lanes
5–7), TFO2 (lanes 8–10), TFO18 (lanes 11–13),
TFO20 (lanes 14–16 ), 20 µM
TFO3 (lane 4) and no TFOs (lanes 1-3). Samples were then incubated
with the nuclear extracts from PMA-treated K562 cells except in
lane 2, which contained labeled duplex only. In lane 3, 20-fold
more unlabeled duplex target was added. a and b, protein–DNA
complexes; c, free duplex probe.