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bioRxiv · 10.1101/296665

Craniofacial traits determined by neural crest cells-restricted expression of Dlx5/6: probing the origin of matching functional jaws

Shimizu, M.·Narboux-Neme, N.·Gitton, Y.·de Lombares, C.·Fontaine, A.·Alfama, G.·Kitazawa, T.·Kawamura, Y.·Heude, E.·Marshall, L.·Higashiyama, H.·Wada, Y.·Kurihara, Y.·Kurihara, H.·Levi, G.
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Abstract

Gnathostome jaws derive from the first pharyngeal arch (PA1), a complex structure constituted by Neural Crest Cells (NCCs), mesodermal, ectodermal and endodermal cells. Here, to determine the regionalized morphogenetic impact of Dlx5/6 expression, we specifically target their inactivation or overexpression to NCCs. NCC-specific Dlx5/6 inactivation (NCC{Delta}Dlx5/6) generates severely hypomorphic lower jaws that present typical maxillary traits. Therefore, differently from the symmetric jaws obtained after constitutive Dlx5/6 inactivation, NCC{Delta}Dlx5/6 embryos present a strikingly asymmetric mouth. Reciprocally, forced Dlx5 expression in maxillary NCCs provokes the appearance of distinct mandibular characters in the upper jaw. We conclude that: 1) Dlx5/6 activation in NCCs invariably determines lower jaw identity; 2) the morphogenetic processes that generate functional matching jaws depend on the harmonization of Dlx5/6 expression in NCCs and in distinct ectodermal territories. The co-evolution of synergistic opposing jaws requires the coordination of distinct regulatory pathways involving the same transcription factors in distant embryonic territories.

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Shimizu, M., Narboux-Neme, N., Gitton, Y., de Lombares, C., Fontaine, A., Alfama, G., Kitazawa, T., Kawamura, Y., Heude, E., Marshall, L., Higashiyama, H., Wada, Y., Kurihara, Y., Kurihara, H., Levi, G.. 2018-04-06. Craniofacial traits determined by neural crest cells-restricted expression of Dlx5/6: probing the origin of matching functional jaws. https://doi.org/10.1101/296665

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