GSE127143
Cytokine-sensing primary enhancer cluster launches secondary enhancers to activate multi-gene locus [Hi-C]
Enhancer clusters are platforms occupied at high-density by the transcription machinery to activate lineage-specific genes. However, it is not clear yet whether they are merely a collection of conventional enhancers or represent unique and new types of regulatory elements. Specifically, the question remains whether they activate additional enhancer programs in multigene loci. We addressed this issue in the mouse mammary gland, where genes are highly activated during pregnancy. We identify a 300kb multi-gene locus with twenty-one regulatory elements, including a cytokine-dependent primary enhancer cluster (PEC). Using genome editing in combination with ChIP-seq, RNA-seq and 3C-technologies, we show that the PEC initiates the activation of lineage-specific genes through contacting and activating secondary enhancers. This new framework of enhancer clusters indicates a hitherto unrecognized hierarchy of regulation by which a PEC activates genes via regulating secondary enhancers. Overall design: Hi-C for mammary tissues of wild type mice.