Epigenetic mechanisms that regulate cell identity.

Individual cell fate decisions can vary according to changes in gene expression in response to environmental, developmental, or metabolic cues. This plasticity is tightly regulated during embryonic development and mediated by the exquisitely coordinated activation and repression of groups of genes. Genes that become repressed are immersed in a condensed chromatin environment that renders them refractory to stimulation. This mechanism is responsible for both the loss of cell plasticity during differentiation and the preservation of cell identity. Understanding the molecular events involved in the establishment and maintenance of these restrictive domains will benefit the design of strategies for cellular reprogramming, differentiation, and cancer treatment.