FIG. 3.
Sp1 enhances recruitment of TFIID to the A20 promoter. (A) Schematic representation of A20 promoter organization and the mutated promoters used for the subsequent experiments. (B) NF-κB does not change core promoter occupancy by TFIID in vitro. DNA fragments of wild-type (WT) and NF-κB-mutated promoter were immobilized on magnetic beads and used for a binding reaction with Jurkat nuclear extract supplemented with purified recombinant p65/Re1A. The bound proteins were eluted from the beads and analyzed by immunoblotting with antibodies against p65/Re1A, TBP, and TAFII250. (C) DNA binding by Sp1 is correlated with increased TFIID association with the A20 promoter. Immobilized template-binding reactions with wild-type and Sp1-mutated A20 promoter and Jurkat cell nuclear extract prepared from nonstimulated cells are shown.