title: Expression of Pax-3 is initiated in the early neural plate by posteriorizing signals produced by the organizer and by posterior non-axial mesoderm.
abstract: Pax-3 is a paired-type homeobox gene that is specifically expressed in the dorsal and posterior neural tube. We have investigated inductive interactions that initiate Pax-3 transcript expression in the early neural plate. We present several lines of evidence that support a model where Pax-3 expression is initiated by signals that posteriorize the neuraxis, and then secondarily restricted dorsally in response to dorsal-ventral patterning signals. First, in chick and Xenopus gastrulae the onset of Pax-3 expression occurs in regions fated to become posterior CNS. Second, Hensen's node and posterior non-axial mesoderm which underlies the neural plate induce Pax-3 expression when combined with presumptive anterior neural plate explants. In contrast, presumptive anterior neural plate explants are not competent to express Pax-3 in response to dorsalizing signals from epidermal-ectoderm. Third, in a heterospecies explant recombinant assay with Xenopus animal caps (ectoderm) as a responding tissue, late, but not early, Hensen's node induces Pax-3 expression. Chick posterior non-axial mesoderm also induces Pax-3, provided that the animal caps are neuralized by treatment with noggin. Finally we show that the putative posteriorizing factors, retinoic acid and bFGF, induce Pax-3 in neuralized animal caps. However, blocking experiments with a dominant-inhibitory FGF receptor and a dominant-inhibitory retinoic acid receptor suggest that Pax-3 inductive activities arising from Hensen's node and posterior non-axial mesoderm do not strictly depend on FGF or retinoic acid.
authors.affiliation: Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Bang
authors.forename: N
authors.initials: N
authors.lastname: Papalopulu
authors.forename: C
authors.initials: C
authors.lastname: Kintner
authors.forename: M D
authors.initials: MD
authors.lastname: Goulding
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002352:Carrier Proteins; D002490:Central Nervous System / Q000196:embryology* / Q000378:metabolism; D002642:Chick Embryo; D046508:Culture Techniques; D004268:DNA-Binding Proteins / Q000235:genetics*; D004475:Ectoderm / Q000502:physiology; D004627:Embryonic Induction / Q000235:genetics; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005775:Gastrula / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018398:Homeodomain Proteins; D008648:Mesoderm / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics; D051857:Otx Transcription Factors; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D011506:Proteins / Q000235:genetics / Q000502:physiology; D011784:Quail / Q000196:embryology; D012333:RNA, Messenger / Q000032:analysis; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D000072482:Retinoic Acid Receptor alpha; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors; D014212:Tretinoin / Q000494:pharmacology; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology; D000099176:Noggin Protein
chemical_list: D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D016222:Fibroblast Growth Factor 2; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D051857:Otx Transcription Factors; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D011506:Proteins; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D015534:Trans-Activators; D014157:Transcription Factors; D014212:Tretinoin; D029867:Xenopus Proteins; D000099176:Noggin Protein; C525810:Bmp4 protein, mouse; C489411:Pax3 protein, Xenopus; C000607072:Rara protein, mouse; C525812:bmp4 protein, Xenopus; C068686:Pax3 protein, mouse