Figure 1.
Top: under normal developmental conditions, DNMT1 levels in adult progenitor cells are low, leading to sparse DNA methylation (shown in red) at the promoter of RARα gene. Low levels of DNA methylation allow for high RARα gene expression, which is necessary for normal levels of differentiation into neurons. Bottom: exposure to maternal separation during the first 2 weeks of life increases DNMT1 levels in adult progenitor cells, leading to increased DNA methylation, reduced RARα expression, and decreased capacity to differentiate into neurons in vitro. DNMT1, DNA (cytosine-5-)-methyltransferase 1; RAR, retinoic acid receptor.