Interferon response sequence potentiates activity of an enhancer in the promoter region of a mouse H-2 gene.

The expression of class I transplantation antigens encoded in the major histocompatibility complex (H-2 in mouse, HLA in man) can be induced by alpha-, beta- and gamma-interferons. Both transcriptional and post-transcriptional mechanisms have been postulated. Recently, a common sequence has been found in the promoter region of several human genes responsive to IFN-alpha. The promoters of H-2Kb and several other mouse class I genes contain a similar interferon response sequence. We show here, in a transient assay, that the H-2Kb promoter can be induced by all three types of interferon and that the interferon response sequence is necessary for induction to occur. However, the response sequence is active only when associated with a functional enhancer sequence which we have recently identified in the promoter of H-2Kb and other class I genes. The combination of these two sequences can render a heterologous promoter responsive to interferon, irrespective of its orientation relative to the cap site.