title: Evidence for a myotomal Hox/Myf cascade governing nonautonomous control of rib specification within global vertebral domains.
abstract: Hox genes are essential for the patterning of the axial skeleton. Hox group 10 has been shown to specify the lumbar domain by setting a rib-inhibiting program in the presomitic mesoderm (PSM). We have now produced mice with ribs in every vertebra by ectopically expressing Hox group 6 in the PSM, indicating that Hox genes are also able to specify the thoracic domain. We show that the information provided by Hox genes to specify rib-containing and rib-less areas is first interpreted in the myotome through the regional-specific control of Myf5 and Myf6 expression. This information is then transmitted to the sclerotome by a system that includes FGF and PDGF signaling to produce vertebrae with or without ribs at different axial levels. Our findings offer a new perspective of how Hox genes produce global patterns in the axial skeleton and support a redundant nonmyogenic role of Myf5 and Myf6 in rib formation.
authors.affiliation: Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
authors.forename: Tânia
authors.initials: T
authors.lastname: Vinagre
authors.forename: Natalia
authors.initials: N
authors.lastname: Moncaut
authors.forename: Marta
authors.initials: M
authors.lastname: Carapuço
authors.forename: Ana
authors.initials: A
authors.lastname: Nóvoa
authors.forename: Joana
authors.initials: J
authors.lastname: Bom
authors.forename: Moisés
authors.initials: M
authors.lastname: Mallo
mesh_terms: D000818:Animals; D001846:Bone Development; D005346:Fibroblast Growth Factors / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008954:Models, Biological; D008957:Models, Genetic; D024510:Muscle Development; D051787:Myogenic Regulatory Factor 5 / Q000502:physiology*; D018006:Myogenic Regulatory Factors / Q000502:physiology*; D010641:Phenotype; D010982:Platelet-Derived Growth Factor / Q000378:metabolism
chemical_list: D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins; C497418:Myf5 protein, mouse; D051787:Myogenic Regulatory Factor 5; D018006:Myogenic Regulatory Factors; D010982:Platelet-Derived Growth Factor; C063403:myogenic factor 6; C092119:Hoxa10 protein, mouse; D005346:Fibroblast Growth Factors