Enhancers are released from the periphery during T-cell activation. (A) Upon stimulation of naïve CD4+ T cells with PMA, 513 out of 974 putative enhancer clusters identified by Hnisz et al. (2013) are induced (red), while only 107 are silenced (blue). (B) Of the 513 induced enhancer clusters, 27 were in LADs in resting Jurkat T cells (black circle). Of these, 17 become released upon T-cell activation (yellow circle). (C) A 66-kbp Chromosome 3 region containing a putative enhancer induced during T-cell activation releases from the periphery (PI) in activated Jurkat T cells. In addition to Jurkat activation DamID and gene expression tracks, ChIP-seq tracks from primary naïve and PMA-activated CD4+ T cells for H3K4me1 and H3K27ac histone modifications marking active enhancers are shown (data from Bernstein et al. 2010). The H3K27ac peaks defined as enhancers (Enh.) and super enhancers (S. Enh.) by Hnisz et al. (2013) are also displayed as tracks. (D) Quantification of putative enhancer position in resting and activated Jurkat T cells relative to Lamin B2, confirming its activation-induced release. For quantification statistics, the position of loci in the activated sample was compared to the resting sample by KS tests. (***) P < 0.001. Distance measurements were performed on a minimum of 50 nuclei per sample.
