Analysis of NF-

κB/Rel binding to the putative NF-κB/Rel binding sites from the human TRAF1 promoter in B-CLL lymphocytes. Electrophoretic mobility shift assays were performed with nuclear extracts from B cells of 2 patients with B-CLL and the labeled H2TF1 binding site as a probe. Constitutive NF-κB/Rel binding is shown in both patients (lane 1) and was competed by a 20-fold excess of the unlabeled H2TF1 oligonucleotide (lane 2) but not by a 20-fold excess of an unlabeled Oct-1 oligonucleotide (lane 3). Unlabeled double-stranded oligonucleotides spanning the putative NF-κB/Rel binding sites 1-5 of the human TRAF1 promoter region were used as competitors at a 20-fold (lanes 4, 6, 8, 10, 12) or a 100-fold (lanes 5, 7, 9, 11, 13) molar excess. The specific NF-κB/Rel binding complexes consisting of a slower migrating p50/p655 heterodimer and a faster migrating p50 homodimer are indicated by arrows. NS corresponds to nonspecific binding.