"Study mapped H2A.Z genome-wide in embryonic stem cells and neural progenitors; H2A.Z is deposited at promoters and enhancers and correlates strongly with H3K4 methylation. H2A.Z is present at poised promoters with bivalent chromatin and at active promoters with H3K4 methylation but is absent from stably repressed promoters that are enriched for H3K27 trimethylation."xsd:string