Functional interactions between Mi-2ß and AP1 complexes control response and recovery from barrier disruption

Keratinocytes respond to environmental signals by eliciting induction of genes that preserve skin's integrity. Here we show that the transcriptional response to stress signaling is supported by short-lived epigenetic changes. Comparison of chromatin accessibility and transcriptional changes induced by barrier disruption or by loss of the nucleosome remodeler Mi-2ß identified their striking convergence in mouse and human keratinocytes. Mi-2ß directly repressed genes induced by barrier disruption by restricting AP1-enriched promoter-distal sites, occupied by Mi-2ß and JUNB at steady state and by c-JUN after Mi-2ß depletion or stress signaling. Barrier disruption led to a modest reduction in Mi-2ß expression and a further selective reduction of Mi-2ß localization at stress response genes possibly through competition with activated c-JUN. Consistent with a repressive role at stress response genes, genetic ablation of Mi-2ß did not prevent re-establishment of barrier integrity but was required for return to homeostasis. Thus a competition between Mi-2ß repressive and activating AP1 complexes may permit rapid transcriptional response to and resolution from stress signaling. Overall design: 24 mRNA-seq, 8 ATAC-seq, 22 ChIP_seq samples