The BAF chromatin remodeling subunit ARID1B coordinates cell-cycle exit and motor neuron differentiation

ARID1B is essential for the transition from proliferating neural progenitors to postmitotic motor neurons in Arid1b knockout mouse embryonic stem cells, impairing cell-cycle exit and neurite outgrowth.

• Why it matters: Motor dysfunction linked to Arid1b mutations suggests ARID1B regulates motor neuron specification, but its role in the developmental switch to postmitotic neurons was unclear.
• What they did: Using Arid1b knockout mouse embryonic stem cells, the study assessed cell-cycle exit, neurite outgrowth, and neuronal gene expression, and mapped ARID1B-containing BAF recruitment to neuronal promoters.
• The result: ARID1B-containing BAF complexes are recruited to neuronal gene promoters enriched for active chromatin signatures and NRF1 binding, with p300 preferentially occupying ARID1B/BRG1 co-bound regions; ARID1B loss reduces H3K27ac enrichment linked to neuronal gene expression.