Lhx6 regulates tooth root patterning and morphogenesis

We show in vivo evidence that Lhx6 is a key regulator of tooth root patterning. Lhx6 is consistently and specifically expressed in the dental mesenchyme in mice after birth. Unexpectedly, despite the fact that Lhx6 is broadly expressed in dental mesenchyme during embryonic tooth crown development, it labels a subpopulation of Gli1+ root progenitor cells in the apical dental mesenchyme during postnatal root development. The progeny of this Lhx6+ cell subpopulation is closely associated with root furcation development, and loss of Lhx6 results in root furcation and number of defects. Mechanistically, Lhx6 regulates tooth root patterning and morphogenesis through coordinating key cellular events including mesenchymal proliferation and differentiation as well as dental epithelial elongation.