title: beta-catenin in epithelial morphogenesis: conversion of part of avian foot scales into feather buds with a mutated beta-catenin.
abstract: We explored the role of beta-catenin in chicken skin morphogenesis. Initially beta-catenin mRNA was expressed at homogeneous levels in the epithelia over a skin appendage tract field which became transformed into a periodic pattern corresponding to individual primordia. The importance of periodic patterning was shown in scaleless mutants, in which beta-catenin was initially expressed normally, but failed to make a punctuated pattern. To test beta-catenin function, a truncated armadillo fragment was expressed in developing chicken skin from the RCAS retrovirus. This produced a variety of phenotypic changes during epithelial appendage morphogenesis. In apteric and scale-producing regions, new feather buds with normal-appearing follicle sheaths, dermal papillae, and barb ridges were induced. In feather tracts, short, wide, and curled feather buds with abnormal morphology and random orientation formed. Epidermal invaginations and placode-like structures formed in the scale epidermis. PCNA staining and the distribution of molecular markers (SHH, NCAM, Tenascin-C) were characteristic of feather buds. These results suggest that the beta-catenin pathway is involved in modulating epithelial morphogenesis and that increased beta-catenin pathway activity can increase the activity of skin appendage phenotypes. Analogies between regulated and deregulated new growths are discussed.
authors.affiliation: Department of Pathology, School of Medicine, Los Angeles, California, 90033, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: Widelitz
authors.forename: T X
authors.initials: TX
authors.lastname: Jiang
authors.forename: J
authors.initials: J
authors.lastname: Lu
authors.forename: C M
authors.initials: CM
authors.lastname: Chuong
mesh_terms: D025601:Adenomatous Polyposis Coli Protein; D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002642:Chick Embryo; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D004848:Epithelium / Q000196:embryology / Q000378:metabolism; D005241:Feathers / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D051821:Lymphoid Enhancer-Binding Factor 1; D009154:Mutation; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012867:Skin / Q000196:embryology* / Q000378:metabolism*; D014018:Tissue Distribution; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics; D014161:Transduction, Genetic; D051176:beta Catenin
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D010446:Peptide Fragments; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D051176:beta Catenin