title: Combined function of HoxA and HoxB clusters in neural crest cells.
abstract: The evolution of chordates was accompanied by critical anatomical innovations in craniofacial development, along with the emergence of neural crest cells. The potential of these cells to implement a craniofacial program in part depends upon the (non-)expression of Hox genes. For instance, the development of jaws requires the inhibition of Hox genes function in the first pharyngeal arch. In contrast, Hox gene products induce craniofacial structures in more caudal territories. To further investigate which Hox gene clusters are involved in this latter role, we generated HoxA;HoxB cluster double mutant animals in cranial neural crest cells. We observed the appearance of a supernumerary dentary-like bone with an endochondral ossification around a neo-Meckel's cartilage matrix and an attachment of neo-muscle demonstrating that HoxB genes enhance the phenotype induced by the deletion of the HoxA cluster alone. In addition, a cervical and hypertrophic thymus was associated with the supernumerary dentary-like bone, which may reflect its ancestral position near the filtrating system. Altogether these results show that the HoxA and HoxB clusters cooperated during evolution to lead to present craniofacial diversity.
authors.affiliation: School of Life Sciences, Federal Institute of Technology (EPFL) Lausanne, Switzerland.
authors.forename: Maxence
authors.initials: M
authors.lastname: Vieux-Rochas
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Mascrez
authors.forename: Robb
authors.initials: R
authors.lastname: Krumlauf
authors.forename: Denis
authors.initials: D
authors.lastname: Duboule
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000196:embryology / Q000378:metabolism; D001921:Brain / Q000196:embryology / Q000378:metabolism; D005145:Face; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006984:Hypertrophy; D051379:Mice; D008817:Mice, Mutant Strains; D009024:Morphogenesis / Q000235:genetics; D005810:Multigene Family; D009132:Muscles / Q000196:embryology / Q000378:metabolism; D009432:Neural Crest / Q000166:cytology* / Q000196:embryology / Q000378:metabolism*; D010641:Phenotype; D013950:Thymus Gland / Q000196:embryology / Q000378:metabolism / Q000473:pathology
chemical_list: D018398:Homeodomain Proteins
keywords: Craniofacial; Dentary bone; Hox genes; Neural crest cells.; Thymus