NRF1 Association with AUTS2-Polycomb Mediates Specific Gene Activation in the Brain

Polycomb group (PcG) proteins are evolutionarily conserved chromatin-modifying factors that regulate gene expression to control tissue development. We previously discovered an AUTS2?Polycomb complex activates gene expression by recruiting Casein kinase 2 (CK2) and P300. But the mechanisms underlying the recruitment of AUTS2-PRC1 to chromatin and the physiological relevance of AUTS2-P300 interaction during neurodevelopment remain unknown. Here, we report that the transcription factor Nuclear Respiratory Factor 1 (NRF1) physically interacts with AUTS2 and overlaps with AUTS2 on chromatin binding. In a functional study combined with the single cell RNA-seq approach, we demonstrate that NRF1 is required for AUTS2 recruitment to chromatin, ncPRC1 associated active transcription in motor neuron and thereby modulates multipotent progenitors to motor neuron differentiation. Moreover, we discover that mutations within AUTS2 HX repeat region, which associate with RSTS phenotype disrupt AUTS2-P300 interaction and AUTS2 mediated transcriptional activation. Together, these findings reveal the underlying mechanism by which the AUTS2-containing ncPRC1 complex is recruited and activates transcription and mutations in the AUTS2 HX repeat region exert a dominant negative effect on AUTS2-P300 mediated transcriptional activation in RSTS. Overall design: ChIP-seq for AUTS2-PRC1 complex and NRF1 in mouse brain, mESCc, in vitro differentiated motor neuron under WT, Auts2, Nrf1 knockout condition, as well as scRNA-seq in MN under WT, Auts2, Nrf1 knockout condition.