IFN-inducible DNA binding complex detected by BG1 probe of Ly-6E is identical to the inducible complex detected by O15 probe derived from ISG-15 gene. Identity and specificity of the binding complex is shown by the ability of these sequences to cross-compete with each other when present in a 100-fold molar excess (lanes 6 and 9). Effect of anti-STAT1 and anti-STAT3 antibodies on the formation of these complexes by BG1 probe is also shown (lanes 10 and 11).