Induction of the Ly-6A/E Gene by Interferon α/β and γ Requires a DNA Element to which a Tyrosine-Phosphorylated 91-kDa Protein Binds

The murine Ly-6A/E gene is transcriptionally induced in cells exposed to interferon α/β or γ (IFN-α/β or IFN-γ). Analysis of the 5' flanking sequence using reporter plasmids that contain upstream elements of the Ly-6E gene has previously identified an ≈850-base-pair IFN-responsive region that lacked an IFN-α-stimulated response element (ISRE), the element present and required for an IFN-α response of a number of genes. Analysis by deletion and stable transfection of the IFN-responsive region of the Ly-6E promoter has defined an 80-base-pair region containing an IFN-γ activation site (GAS) but no ISRE that allows IFN-γ and IFN-α inducibility of the Ly-6E gene. As tested by specific antiserum, a 91-kDa protein known to be activated in IFN-α- or IFN-γ-treated cells binds to the GAS element from the Ly-6E promoter. The 91-kDa protein exists as an inactive cytoplasmic precursor and depends on tyrosine phosphorylation for its activation. Thus the same 91-kDa protein appears to act in the signal transduction pathways of both types of IFN for the Ly-6-A/E gene.