The DLX2-LAP2α axis licenses ectomesenchymal specification by unlocking chromatin barriers for craniofacial regeneration [CUT&Tag]

The ectomesenchyme generates much of the craniofacial skeleton, sutures, and diverse connective tissues in the mammalian head, yet its derivation from embryonic stem cells (ESCs) and the underlying molecular drivers remain poorly defined. Here, we identified Dlx2 as a key regulator that efficiently directed murine ESCs towards Msx1+ ectomesenchyme, recapitulating the developmental trajectory. These Msx1+ progenitors expressed classical craniofacial markers and retained robust osteochondral bipotency in vitro and in vivo. Mechanistically, DLX2 utilized a lamina-associated polypeptide 2 (LAP2)-dependent nuclear chaperoning system, engaging LAP2α via a 38-amino-acid homeodomain motif to interact with nucleosomes, thereby opening chromatin and activating a craniofacial ectomesenchymal gene network. Disrupting DLX2-LAP2α interaction or silencing Dlx2 targets largely diminished ectomesenchymal differentiation. Our findings established DLX2 as a pioneer factor in ectomesenchyme specification, offering insights into craniofacial development and stem cell engineering.