title: Abortive placode formation in the feather tract of the scaleless chicken embryo.
abstract: The featherless phenotype of the scaleless mutant provides a model for delineating the process of feather follicle formation. Initial studies established that the mutation affects the epidermis and suggested that epidermis is unable to respond to signals from underlying dermis, or propagate a reciprocal signal. The work presented here demonstrates that scaleless epidermis does indeed respond to the initial inductive signals from dermis, as indicated by the localization of nuclear beta-catenin and transient focal expression of genes expressed in the placode of wild-type feather rudiments. In the sporadic "escaper" feathers that form in scaleless, expression of many genes associated with the progression of feather development is comparable to that in wild-type embryos. An exception is the ectodysplasin receptor gene Edar, which is expressed at lower levels in mutant feather buds. These observations suggest that the scaleless mutation impairs the locally augmented expression of Edar required to stabilize the placodal fate and sustain feather development.
authors.affiliation: Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Houghton
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Lindon
authors.forename: Allison
authors.initials: A
authors.lastname: Freeman
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Morgan
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002642:Chick Embryo; D053331:Ectodysplasins / Q000378:metabolism; D053339:Edar Receptor / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology* / Q000378:metabolism; D005241:Feathers / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D053537:Keratin-17 / Q000378:metabolism; D009024:Morphogenesis / Q000235:genetics*; D009154:Mutation; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D053331:Ectodysplasins; D053339:Edar Receptor; D053537:Keratin-17; D051153:Wnt Proteins; D051176:beta Catenin