title: Overexpression of Xgsk-3 disrupts anterior ectodermal patterning in Xenopus.
abstract: The Xenopus homolog of glycogen synthase kinase-3, Xgsk-3, plays a major role in regulating the formation of the dorsal-ventral axis, most likely through effects on the mesoderm. To determine whether Xgsk-3 is involved in ectodermal patterning, Xgsk-3 was ectopically overexpressed in the presumptive ectoderm. This approach resulted in a dramatically expanded cement gland, which is due to early changes in cement gland specification at the anterior end of the embryo. Explant experiments were used to show that Xgsk-3 overexpression enhances the response of ectoderm to cement-gland-inducing signals from the mesoderm and to the intercellular signaling factor noggin. Expression of two other noggin-inducible genes, Xotx2 and XANF-2, was also expanded in whole embryos, while the expression of the epidermal marker, Xgbx-2, was eliminated. These results suggest that Xgsk-3 may play a role in anterior ectodermal patterning as a component of an intracellular pathway that regulates the ectodermal responsiveness to endogenous inducing signals.
authors.affiliation: Department of Biochemistry, University of Washington, Seattle 98195-7350, USA.
authors.forename: S B
authors.initials: SB
authors.lastname: Pierce
authors.forename: D
authors.initials: D
authors.lastname: Kimelman
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000502:physiology*; D002352:Carrier Proteins; D004475:Ectoderm / Q000648:ultrastructure*; D004625:Embryo, Nonmammalian / Q000201:enzymology / Q000648:ultrastructure; D047108:Embryonic Development; D004627:Embryonic Induction / Q000502:physiology*; D004790:Enzyme Induction; D004817:Epidermis / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D005822:Genetic Vectors; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D006257:Head / Q000002:abnormalities / Q000196:embryology*; D008648:Mesoderm / Q000502:physiology; D008845:Microinjections; D009420:Nervous System / Q000196:embryology; D011506:Proteins / Q000502:physiology; D012333:RNA, Messenger / Q000008:administration & dosage / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics; D000099176:Noggin Protein
chemical_list: D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002352:Carrier Proteins; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D011506:Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D000099176:Noggin Protein