Abortive placode formation in the feather tract of the scaleless chicken embryo

• Published in: Developmental dynamics Vol. 236; no. 11; pp. 3020 - 3030
• Main Authors: Houghton, Leslie, Lindon, Catherine M., Freeman, Allison, Morgan, Bruce A.
• Format: Journal Article
• Language: English
• Published: New York Wiley‐Liss, Inc 01-11-2007
• Subjects: Animals; beta Catenin - metabolism; Bone Morphogenetic Proteins - metabolism; Cell Differentiation; Chick Embryo; ectodysplasin; Ectodysplasins - metabolism; Edar Receptor - metabolism; Epidermis - cytology; Epidermis - embryology; Epidermis - metabolism; feather; Feathers - embryology; Feathers - metabolism; Gene Expression Regulation, Developmental; Keratin-17 - metabolism; Morphogenesis - genetics; Mutation; pattern formation; scaleless; Signal Transduction; Wnt Proteins - metabolism
• ISSN: 1058-8388; 1097-0177
• DOI: 10.1002/dvdy.21337

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 β‐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. Developmental Dynamics 236:3020–3030, 2007. © 2007 Wiley‐Liss, Inc.