EMSA using nuclear extracts from retrovirus-transduced KG1a cells cultured with or without IFN-γ (A). The nuclear extracts were incubated with or without competitor cold probe (100×). SIF, sis-inducible factor. (B) The nuclear extracts were incubated with or without normal rabbit serum (NRS) or anti-Stat1α or anti-Stat3 antibody. The arrows in the right side indicate the position of supershifted bands. This figure clearly shows three bands corresponding to SIF-A, SIF-B, and SIF-C. In IFN-γ–treated lanes, these bands were too strong to be clearly separated. However, these three lanes are clearly distinguishable in unstimulated lanes.