Chromatin structure and gene expression programs of human embryonic and induced pluripotent stem cells.

Knowledge of both the global chromatin structure and the gene expression programs of human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) should provide a robust means to assess whether the genomes of these cells have similar pluripotent states. Recent studies have suggested that ESCs and iPSCs represent different pluripotent states with substantially different gene expression profiles. We describe here a comparison of global chromatin structure and gene expression data for a panel of human ESCs and iPSCs. Genome-wide maps of nucleosomes with histone H3K4me3 and H3K27me3 modifications indicate that there is little difference between ESCs and iPSCs with respect to these marks. Gene expression profiles confirm that the transcriptional programs of ESCs and iPSCs show very few consistent differences. Although some variation in chromatin structure and gene expression was observed in these cell lines, these variations did not serve to distinguish ESCs from iPSCs.