FAZF and PLZF bind to the same DNA sequences. (A) Nuclear extracts from untransfected cells (control) or from 293T cells transfected with a PLZF expression vector or a Flag-FAZF expression vector were allowed to interact with a high affinity PLZF binding site (Site B, Table 1), followed by nondenaturing gel electrophoresis. A supershift assay of the Flag-FAZF complexes was performed by the addition of Flag M2 MoAb to the reaction. (B) Competition analysis of FAZF and PLZF DNA binding. Extracts containing PLZF or FAZF were allowed to bind to a high affinity PLZF site (Site B, Table 1) in the absence of competitor or in the presence of a 10-fold, 100-fold, or 1,000-fold molar excess of the indicated unlabeled competitor oligonucleotide. The DNA protein complexes were resolved as described above.