Transription activation of IFN-beta gene. Computer model showing the molecular structure of an enhanceosome (dark green, purple, orange and red) containing the transcription factors IRF-3, ATF-2 and c-Jun bound to the interferon-beta (IFN-beta) enhancer on a strand of DNA (deoxyribonucleic acid, green). Activation of the IFN-beta gene requires assembly of an enhanceosome containing a number of transcription factors including the ones shown here. These factors bind to the relevant site on the DNA strand and activate expression of the IFN-beta gene.