Human β-interferon gene expression is regulated by an inducible enhancer element

We have localized the regulatory sequence required for viral or poly(I)-poly(C) activation of human beta-interferon gene expression to a region located between -37 and -77 from the mRNA cap site. This sequence has the characteristics of an inducible enhancer element: it can act upstream or downstream of the beta-interferon gene regardless of its orientation, and at distances up to approximately 1 kilobase from its normal location. Moreover, this element can confer inducibility on a heterologous promoter. Further analysis has identified a minimal regulatory element of 14 base pairs within this enhancer. Sequences closely related to this element are present five times within the 5'-flanking regions of both the alpha- and beta-interferon genes. The number of these minimal regulatory elements required for maximal beta-interferon gene expression appears to differ in different cell lines.