LIL-Stat binding activity is not observed in monocytes. Nuclear extracts derived from control, IL-1β–, and IFN-γ–treated monocytes were incubated with the ³²P-labeled oligonucleotides specific for LIL-Stat (lanes 1-7) and Stat1 (lanes 8-16). Lanes 6 and 15 represent the respective labeled oligonucleotides alone. Competition was performed by addition of a 100-fold molar excess of unlabeled LIL-Stat oligonucleotide (lane 7) or unlabeled Stat1 oligonucleotide (lane 16). Specificity of Stat1 oligonucleotide was confirmed by supershift experiments with the anitbodies against Stat1N and Stat1C (lanes 13, and 14, respectively).