Nature | 基因放在哪，比修饰更重要——空间表观遗传学揭秘人类大脑发育新机制

TL;DR - A Nature study maps subnuclear genome organization during human fetal cortical development and finds that relocating developmental genes from the nuclear lamina to nuclear speckles drives their activation. The work shows that physical nuclear positioning can regulate transcription independently of canonical histone modifications.

• During differentiation from radial glia to neurons, lamina-associated domains underwent 23% genome-wide reorganization; 305 of 739 released genes moved directly to transcriptionally active nuclear speckles.
• Among bivalent genes undergoing this lamina-to-speckle relocation, 85% lost the repressive H3K27me3 mark and expression increased by more than eightfold on average.
• Removing H3K27me3 pharmacologically did not activate genes that remained anchored to the nuclear lamina, indicating that lamina proximity itself strongly represses transcription.
• The lamina permits initial RNA polymerase II recruitment but spatially excludes positive elongation factors while enriching pausing factors, blocking productive transcriptional elongation.