EMSA using human TBP and HTLV-I LTR TATA region. (A) A labeled DNA fragment extending from −40 to −10 was used in binding reactions with TBP (1 FPU). Competition reactions were performed with excess amounts of the homologous (WT Comp, 250-fold) or heterologous (250-fold) competitors, including the HTLV-I LTR fragment with the TATAA-to-AGAAC 5-bp mutant TATA (Mut Comp), a TBP consensus oligonucleotide with a TATA box, and an NF-κB oligonucleotide. The TBP-TATA complex band (arrow) and unbound radiolabeled probe (Free Probe) are indicated. (B) The same probe as in A was incubated with TBP (1 FPU), GST, or GST-p53 wild-type at 3 levels: 50, 100, and 200 ng. (C) 200 ng GST, GST-p53 wild-type, or GST-p53 with a mutation at codon 135 (GST-p53 Mut) was incubated to reaction mixtures with TBP.