Chromatin restructuring during neurodevelopment. Visual representation of the chromatin restructuring that occurs during neurodevelopment, from ESCs to NPCs and finally to either neurogenesis or gliogenesis. The strength of chromatin compartments fluctuates during this process. ESCs exhibit strong A compartments (dark green), gradually decreasing in strength (light green) during differentiation from NPCs to neurons/glial cells. Conversely, the B compartment in ESCs is relatively weak (light blue) and becomes stronger through differentiation (blue and dark blue). Global histone levels follow a similar pattern as H3K9me3 (histone mark of inactive chromatin) increases through differentiation (light gray to dark gray), in converse to H3K27ac (histone mark of active chromatin), which decreases relative to ESC levels (dark gray to light gray). Zoomed-in examples show the regulation of specific genes. In ESCs, CHD4 (purple) mediates transcriptional silencing of Tbx3, a differentiation factor required for cells leaving the ESC state. In NPCs, there is contact between an NPC-specific enhancer and the neural transcription factor gene Sox2 (yellow box), mediated by a CTCF (red teardrop)/cohesin (blue ring) loop. In neurons, MeCP2 (red) and HDAC3 (blue) govern the transcriptional repression of GFAP, while in astrocytes MeCP2 absence from the gene allows RNA polymerase II (yellow) to transcribe GFAP.
