VIRUS INDUCTION OF HUMAN IFN-BETA GENE-EXPRESSION REQUIRES THE ASSEMBLY OF AN ENHANCEOSOME

We present evidence that transcriptional activation of the human inter feron-beta (IFN beta) gene requires the assembly of a higher order tra nscription enhancer complex (enhanceosome). This multicomponent comple x includes at least three distinct transcription factors and the high mobility group protein HMG I(Y). Both the in vitro assembly and in viv o transcriptional activity of this complex require a precise helical r elationship between individual transcription factor-binding sites. In addition, HMG I(Y), which binds specifically to three sites within the enhancer, promotes cooperative binding of transcription factors in vi tro and is required for transcriptional synergy between these factors in vivo. Thus, HMG I(Y) plays an essential role in the assembly and fu nction of the IFN beta gene enhanceosome.