title: The mouse Engrailed-1 gene and ventral limb patterning.
abstract: During vertebrate limb development, positional information must be specified along three distinct axes. Although much progress has been made in our understanding of the molecular interactions involved in anterior-posterior and proximal-distal limb patterning, less is known about dorsal-ventral patterning. The genes Wnt-7a and Lmx-1, which are expressed in dorsal limb ectoderm and mesoderm, respectively, are thought to be important regulators of dorsal limb differentiation. Whether a complementary set of molecules controls ventral limb development has not been clear. Here we report that Engrailed-1, a homeodomain-containing transcription factor expressed in embryonic ventral limb ectoderm, is essential for ventral limb patterning. Loss of Engrailed-1 function in mice results in dorsal transformations of ventral paw structures, and in subtle alterations along the proximal-distal limb axis. Engrailed-1 seems to act in part by repressing dorsal differentiation induced by Wnt-7a, and is essential for proper formation of the apical ectodermal ridge.
authors.affiliation: Ronald O. Perelman Deparment of Dermatology, New York University Medical School 10016, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Loomis
authors.forename: E
authors.initials: E
authors.lastname: Harris
authors.forename: J
authors.initials: J
authors.lastname: Michaud
authors.forename: W
authors.initials: W
authors.lastname: Wurst
authors.forename: M
authors.initials: M
authors.lastname: Hanks
authors.forename: A L
authors.initials: AL
authors.lastname: Joyner
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000196:embryology; D004475:Ectoderm / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005121:Extremities / Q000196:embryology*; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology; D051379:Mice; D009024:Morphogenesis / Q000235:genetics; D009154:Mutation; D013710:Tendons / Q000196:embryology
chemical_list: C080330:En1 protein, mouse; D018398:Homeodomain Proteins