Fig. 7. Competition/bandshift assay using CKO K1 and xrs-5 cytoplasmic cell extracts. The electrophoretic mobility shift assay was performed by adding cytoplasmic (C) cell extracts from xrs-5 (lanes 2-6) or CHO K1 (lanes 7-11) to a mixture containing radiolabeled A3/4 oligonucleotide (lane 1). Some reactions contained no additional competitor DNA (lanes 2 and 7). Lanes 3 and 8 contained 50x molar excess of cold A3/4 competitor, lanes 4 and 9 contained 500x cold A3/4 competitor, lanes 5 and 10 contained 50x non-specific cold competitor and lanes 6 and 11 contained 500x non-specific competitor. The positions of the protein-DNA complexes and of the free probe are indicated.