HA-NFATp binds DNA alone and cooperatively with cJun/cFos. DNase I footprinting assays were performed to investigate the binding of HA-NFATp to a region of the human IL-2 promoter in the absence (lanes 1-5) and presence (lanes 6-10) of recombinant human cJun/cFos (3.2 nM). HA-NFATp was added to reactions at the following final concentrations: 3 nM, lanes 2 and 7; 9 nM, lanes 3 and 8; 27 nM, lanes 4 and 9; and 54 nM, lanes 5 and 10. Footprinting reactions were resolved by denaturing PAGE and analyzed with a Molecular Dynamics PhosphorImager. Positions relative to the transcriptional start site (+1) of the human IL-2 promoter are indicated on the left. Locations of the previously characterized high affinity -45 NFAT site and composite element are indicated on the right.