Abstract
The prevalence of neurodevelopmental disorders (NDDs) in children is increasing, yet their underlying causes remain largely unknown. We identified heterozygous mutations in the Polycomb repressive complex 1 (PRC1) E3 ligases RING1 and RNF2 in individuals with NDDs and revealed distinct mechanisms by which they compromise PRC1 activity. We developed cellular and mouse models carrying the Ring1bR70H variant, which disrupts PRC1/PRC2 recruitment balance and mis-regulates Polycomb target genes. Allele-specific profiling showed that Ring1bR70H preferentially assembles into canonical PRC1 (cPRC1) via the intrinsically disordered region (IDR) of Pcgf2, reducing variant PRC1 (vPRC1) and PRC2.1 binding to chromatin. In Rnf2WT/R70H neuroprecursors, Polycomb complexes aberrantly suppress Wnt signaling, diverting neuroprecursors to non-neuronal lineages and halting neurogenesis. Rnf2R70H/R70H mice are perinatally lethal, while heterozygotes exhibit altered axonal organization, hippocampal and medial prefrontal cortex (mPFC) neuronal imbalances, reduced sociability, and increased anxiety. Our findings reveal an epigenetic mechanism essential for neurodevelopmental integrity and brain function and demonstrate how mutations in Rnf2 disrupt PRC1 occupancy at chromatin, contributing to NDDs.
[Display omitted]
•Discovery of novel missense mutations in RNF2 and RING1 linked to NDDs•Rnf2R70H disrupts the balance of Polycomb complexes co-occupancy at chromatin in ESCs•Rnf2R70H/R70H mice are lethal, and Rnf2WT/R70H mice display brain architectural deficits•Impaired social novelty preference and increased anxiety in Rnf2WT/R70H mice
Borges, González-Blanco, Arigela, et al. report new missense mutations in the PRC1 genes RNF2 and RING1 in individuals with neurodevelopmental disorders. Functional dissection of a deleterious variant reveals that balanced co-recruitment of Polycomb complexes to chromatin is essential for proper neurogenesis and for normal brain function and behavior.