Epigenetics and the timing of neuronal differentiation.

Epigenetic regulation of the genome is required for cell-type differentiation during organismal development and is especially important to generate the panoply of specialized cell types that comprise the brain. Here, we review how progressive changes in the chromatin landscape, both in neural progenitors and in postmitotic neurons, orchestrate the timing of gene expression programs that underlie first neurogenesis and then functional neuronal maturation. We discuss how disease-associated mutations in chromatin regulators can change brain composition by impairing the timing of neurogenesis. Further, we highlight studies that are beginning to show how chromatin modifications are integrated at the level of chromatin architecture to coordinate changing transcriptional programs across developmental including in postmitotic neurons.