Transcriptional activation of the human interferon-beta (IFN-beta) gene by virus 
infection requires the assembly of a higher order nucleoprotein complex, the 
enhanceosome, which consists of the transcriptional activators NF-kappa 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 infection of cells 
results in a dramatic hyperacetylation of histones H3 and H4 that is localized 
to the IFN-beta promoter. Furthermore, expressing a truncated version of IRF-3, 
which lacks a p300/CBP interaction domain, suppresses both histone 
hyperacetylation and activation of the IFN-beta gene. Thus, coactivator-mediated 
localized hyperacetylation of histones may play a crucial role in inducible gene 
expression.