The human beta-interferon gene enhancer is under negative control.

The human beta-interferon gene is regulated by an inducible enhancer element. Analysis of the effect of deletions within this element on beta-interferon transcription indicates that this enhancer is under negative control. Deletion of sequences from the 3' end of the enhancer leads to a dramatic increase in the basal level of beta-interferon mRNA and a decrease in the induction ratio. The remaining 5' region of the enhancer can act as a strong constitutive transcription element, and it shares considerable homology with sequences known to be required for the activity of constitutive viral enhancers. We conclude that the beta-interferon enhancer consists of a constitutive transcription element and a negative regulatory sequence that prevents enhancer activity prior to induction. Thus, derepression of a constitutive transcription element appears to play a key role in the control of human beta-interferon gene expression.