Pluripotency, a property ascribed to the cells that constitute the early embryo as well as to embryonic stem (ES) cells, is progressively lost during differentiation as the activation of lineage-specific programs steer the cell towards a particular fate. The regulation of chromatin structure has emerged as a key mechanism to modulate developmental gene expression patterns by contributing to the activation or silencing of subsets of genes and through maintenance of expression states during subsequent cell divisions. Recent global analyses have revealed key differences in the chromatin landscape in pluripotent embryonic stem (ES) cells as compared to lineage-committed cells, suggesting that chromatin states may be linked to cell fate. Moreover, the molecular and biochemical characterization of a large group of enzymes that regulate chromatin structure and organization has revealed roles for these factors in early development and stem cell function. Such studies have begun to provide critical insights into how the ES cell genome may remain uncommitted, yet poised for differentiation. These findings have broad implications for understanding development as well as the process of re-programming the somatic genome into a pluripotent-like state and of the progression from normal to disease states.
Copyright: © 2009 Ky Sha and Laurie Boyer.