title: Analysis of the expression and function of Wnt-5a and Wnt-5b in developing and regenerating axolotl (Ambystoma mexicanum) limbs.
abstract: Urodele amphibians are unique adult vertebrates because they are able to regenerate body parts after amputation. Studies of urodele limb regeneration, the key model system for vertebrate regeneration, have led to an understanding of the origin of blastema cells and the importance of positional interactions between blastema cells in the control of growth and pattern formation. Progress is now being made in the identification of the signaling pathways that regulate dedifferentiation, blastema morphogenesis, growth and pattern formation. Members of the Wnt family of secreted proteins are expressed in developing and regenerating limbs, and have the potential to control growth, pattern formation and differentiation. We have studied the expression of two non-canonical Wnt genes, Wnt-5a and Wnt-5b. We report that they are expressed in equivalent patterns during limb development and limb regeneration in the axolotl (Ambystoma mexicanum), and during limb development in other tetrapods, implying conservation of function. Our analysis of the effects of ectopic Wnt-5a expression is consistent with the hypothesis that canonical Wnt signaling functions during the early stages of regeneration to control the dedifferentiation of stump cells giving rise to the regeneration-competent cells of the blastema.
authors.affiliation: Developmental Biology Center and Department of Developmental and Cell Biology, University of California at Irvine, California 92697, USA.
authors.forename: Sukla
authors.initials: S
authors.lastname: Ghosh
authors.forename: Stéphane
authors.initials: S
authors.lastname: Roy
authors.forename: Carl
authors.initials: C
authors.lastname: Séguin
authors.forename: Susan V
authors.initials: SV
authors.lastname: Bryant
authors.forename: David M
authors.initials: DM
authors.lastname: Gardiner
mesh_terms: D000558:Ambystoma mexicanum / Q000502:physiology*; D000818:Animals; D015152:Blotting, Northern; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005121:Extremities / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D012038:Regeneration; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D000071818:Wnt-5a Protein
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C084119:MSX2 protein; D051153:Wnt Proteins; C080089:Wnt-5A protein, Ambystoma mexicanum; C080090:Wnt-5B protein, Ambystoma mexicanum; D000071818:Wnt-5a Protein