A, Genome browser image of ChIP-seq for middle and tail Mediator subunits and H3K4me3 HiChIP tracks before and after induction of ER stress at ER stress response gene BHLHE40. H3K4me1 and H3K27ac tracks are from the ENCODE Consortium (GEO accessions GSM945858 and GSM945853). ATF4/Xbp1s binding sites are from publicly available datasets (GEO accessions GSE69304 and GSE49952). 