Virus infection leads to localized hyperacetylation of histones H3 and H4 at the IFN-beta promoter

Transcriptional activation of the human interferon-beta (IFN-beta) gene by virus infection requires the assembly of a higher order nucleoprotein compl ex, the enhanceosome, which consists of the transcriptional activators NF-k appa B (p50/p65), ATF-2/c-jun, IRF-3 and IRF-7, architectural protein HMGI( Y), and the coactivators p300 and CBP. In this report, we show that virus i nfection of cells results in a dramatic hyperacetylation of histones H3 and H4 that is localized to the IFN-beta promoter. Furthermore, expressing a t runcated version of IRF-3, which lacks a p300/CBP interaction domain, suppr esses both histone hyperacetylation and activation of the IFN-beta gene. Th us, coactivator-mediated localized hyperacetylation of histones may play a crucial role in inducible gene expression.