Fig. 1

Epigenetic lineage determination and signal stimulation collaboratively control the enhancers of macrophages. a Without the expression of the master macrophage regulator PU.1, cells do not receive genomic signals not relevant to their own functions. The gene loci exhibit inaccessible chromatin, the suppressive histone marker H3K27me3 and the occupancy of corepressors. b During lineage establishment, the nucleosome in macrophages is evicted more effectively as a result of a relatively prevalent binding of PU.1 that unpacks the tight organization of chromatin. Collaborative TFs, including C/EBP, are subsequently recruited to establish macrophage enhancers. Enhancers are commonly marked by the epigenetic signature H3K4me1. Without activating factors, the genes are poised at baseline, meaning that the enhancers are also marked by H3K27me3 and the binding of repressor complexes. c The presence of local signals, such as TLR4 stimulation, for example, allows for the efficient binding of NF-κB. In addition, the genes lose the H3K27me3 mark on the enhancers and are acetylated at H3K27. These mechanisms facilitate related gene transcription