Epigenetic dynamics during CD4(+) T cells lineage commitment.

T cell lymphopoiesis is a complex, stepwise process in which the transcriptional program of the progenitor cells is progressively adapted in order to generate mature phenotypes. This transcriptional program in differentiated cells is also very flexible, allowing the silencing or activation of critical genes in response to extrinsic or intrinsic stimuli, or, in the case of progenitors, to developmental signals. Thus, progenitor and mature cells must maintain a balance between stability, to preserve their phenotypic identity, and plasticity, to respond and adapt to stimuli. A long-standing question is, therefore, how the transcriptional program is regulated to allow both controlled differentiation and a flexible response. Here we review the contribution of epigenetic mechanisms to transcriptional control during CD4(+) T cell differentiation and the ways in which these mechanisms interact with key transcription factors to ensure proper maturation and maintenance of cell identity. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.