title: A gradient of homeodomain protein in developing forelimbs of Xenopus and mouse embryos.
abstract: The expression of the homeodomain protein XIHbox 1 in developing Xenopus limbs was analyzed using specific antibodies. In the forelimb bud mesoderm XIHbox 1 shows a clear antero-posterior gradient that is strongest in the anterior and proximal region of the forelimb. Hindlimb bud mesoderm is devoid of XIHbox 1, indicating an early molecular difference between arm and leg. The innermost ectodermal cell layer is positive throughout the forelimb and hindlimb bud ectoderm, but no other areas of the skin. Similar results are obtained in developing mouse limbs, suggesting that XIHbox 1 participates in forelimb development in a variety of tetrapods. In early tadpoles analyzed at stages preceding limb bud formation, the lateral plate mesoderm is positive in the region corresponding to the earliest "field" of forelimb information, but not in the hindlimb field. These results suggest a molecular link between morphogenetic fields, gradients, and homeobox genes in vertebrate development.
authors.affiliation: Department of Biological Chemistry, University of California, Los Angeles 90024-1737.
authors.forename: G
authors.initials: G
authors.lastname: Oliver
authors.forename: C V
authors.initials: CV
authors.lastname: Wright
authors.forename: J
authors.initials: J
authors.lastname: Hardwicke
authors.forename: E M
authors.initials: EM
authors.lastname: De Robertis
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000032:analysis*; D005552:Forelimb / Q000196:embryology; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D018398:Homeodomain Proteins; D008648:Mesoderm / Q000032:analysis; D051379:Mice; D009024:Morphogenesis; D009363:Neoplasm Proteins; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C492048:Hoxa7 protein, Xenopus; C492047:Hoxa7 protein, mouse; D009363:Neoplasm Proteins; D029867:Xenopus Proteins