Relative affinity of D dimer-induced proteins for the PAI-1 AP-1–like sequence and the AP-1 consensus sequence. Nuclear proteins from D dimer-exposed fibroblasts (1 μmol/L for 45 minutes) were analyzed by EMSA with a ³²P-PAIcon oligonucleotide (−66 to −45, del-55; TGAGTCA). The indicated molar excesses of unlabeled PAIcon, PAIwt (TGAGTTCA; PAIwt) or PAImut (TGTGTTTG) oligonucleotides were added to the binding reactions, and the reactions were analyzed by EMSA. Band densities of the retarded B complexes were quantified on a phosphorimager. (A) Quantitative competition of protein binding to³²P-labeled PAIcon by unlabeled PAIcon, PAIwt, and PAImut. Data are plotted as band radioactivity (mean + SE) relative to that with no unlabeled PAIcon. (B) Representative EMSA autoradiogram. Lane 1, free labeled PAIcon probe; lanes 2 through 5, labeled PAIcon with indicated molar excesses of unlabeled PAIcon added to the protein binding reaction; lanes 6 through 9, labeled PAIcon with indicated molar excesses of unlabeled PAIwt; and lanes 10 and 11, labeled PAIcon with indicated molar excess of unlabeled PAImut.