Interferon regulatory factor 1 (IRF1) and anti-pathogen innate immune responses
Fig 5
IRF1 contribution to dynamic transcriptional activation networks.
IRF1 binds to GAAA sequences within IRF-E and ISRE enhancers, driving transcriptional activation of target genes. In the case of ISRE binding, IRF1 can form homo- or hetero dimers with other members of the IRF family. In genes with multiple cis-regulatory elements, coordinate binding of IRF1 and other transcription factors such as NF-κB, ISGF3 or GAF to the enhancer region often has a synergistic impact on gene expression. This can be driven by protein-protein interaction-directed formation of enhanceosomes, or co-localization of transcription factors binding to individual cis-elements. IRF1 both modulates and is regulated by activating and repressive epigenetic marks on chromatin, including histone methylation (such as H3K4me3 and H3K27me3) or acetylation at promoter proximal sites.