(A) Multiple STAT complexes bind to the pim-1 GAS element in response to cytokine stimulation. T cells were stimulated with IFN-, IL-2, IL-12, or IL-15 for the indicated times, and nuclear extracts were prepared from the cells. The extracts were incubated with ³²P-labeled pim-1 GAS probe, and the STAT DNA binding was analyzed by EMSA. (B) IFN- induced STAT1, STAT3, and STAT4 DNA binding to pim-1 GAS. T cells were stimulated with IFN- for 30 minutes, and nuclear extracts were prepared. The extracts were incubated for 1 hour on ice with anti-STAT antibodies, followed by binding to ³²P-labeledpim-1 GAS probe. Comparable data were obtained in three independent experiments, each consisting of pooled T cells from two different donors.