CpG Island Structure and Trithorax/Polycomb Chromatin Domains in Human Cells. Homo sapiens

TrxG and PcG complexes play key roles in the epigenetic regulation of development through H3K4me3 and H3K27me3 modification at specific sites throughout the human genome, but how these sites are selected is poorly understood. We find that in pluripotent cells, clustered CpG islands at genes predict occupancy of H3K4me3 and H3K27me3, and these "bivalent" chromatin domains precisely span the boundaries of CpG island clusters. Overall design: Examination of two histone modifications (H3K4me3 and H3K27me3) in human induced pluripotent stem (hiPS) M23F cells.