ISL1 and JMJD3 synergistically control cardiac differentiation of embryonic stem cells (ChIP-Seq). Mus musculus

ISL1 is expressed in cardiac progenitor cells and plays critical roles in cardiac lineage differentiation and heart development. Cardiac progenitor cells hold great potential for clinical and translational applications. However the mechanisms underlying ISL1 function in cardiac progenitor cells have not been fully elucidated. Here we uncover a hierarchical role of ISL1 in cardiac progenitor cells, showing that ISL1 directly regulates hundreds of potential downstream targets that are implicated in cardiac differentiation, through an epigenetic mechanism. Specifically, ISL1 promotes the demethylation of tri-methylation of histone H3K27 (H3K27me3) at the enhancers of key downstream target genes, including Myocd and Mef2c, which are core cardiac transcription factors. ISL1 physically interacts with JMJD3, a H3K27me3 demethylase, and conditional depletion of JMJD3 leads to impaired cardiac progenitor cell differentiation, phenocopying that of ISL1 depletion. Interestingly, ISL1 is not only responsible for the recruitment of JMJD3 to specific target loci during cardiac progenitor differentiation, but also modulates its demethylase activity. In conclusion, ISL1 and JMJD3 partners to alter the cardiac epigenome, instructing gene expression changes that drive cardiac differentiation. Overall design: Examination of ISL1 and JMJD3 genome-wide distribution in day 7 EBs of cardiac differentiated from mESCs.