question: Do histone variant mH2A (macro-H2A) levels decrease upon differentiation?
answer: MacroH2A.1 was found to be present at low levels upon the establishment of pluripotency in the inner cell mass and epiblast, but it was highly enriched in the trophectoderm and differentiated somatic cells later in mouse development. Chromatin immunoprecipitation revealed that macroH2A.1 is incorporated in the chromatin of regulatory regions of pluripotency genes in somatic cells such as mouse embryonic fibroblasts and adult neural stem cells, but not in embryonic stem cells. In addition, overexpression of macroH2A isoforms prevented efficient reprogramming of epiblast stem cells to naïve pluripotency.