In the presence of LPS stimulation alone, IRF-3 and CBP bind to the ifnb1 promoter (top). When macrophages undergoing ER stress (Tpg treatment) are stimulated with LPS, XBP-1, IRF-3, and CBP cooperatively bind the region 6.1kb downstream of the ifnb1 gene. Through chromatin looping, the enhancer bound IRF3 and CBP factors are delivered to the multi-molecular complex at the ifnb1 promoter, ultimately resulting in greater recruitment of transcriptional machinery.