Neural CrestNeurulationNeural TubeEctodermNervous SystemNeural Tube DefectsChick EmbryoAmbystoma mexicanumEmbryo, NonmammalianCentral Nervous SystemSkullIn Situ HybridizationMorphogenesisXenopus ProteinsEmbryo, MammalianGallic AcidAmbystomaGene Expression Regulation, DevelopmentalMicroscopy, Electron, ScanningGastrulaMesodermNotochordMesencephalonPapaverineQuailHeadRhombencephalonBody PatterningXenopus laevisXenopusEmbryonic and Fetal DevelopmentGenes, HomeoboxCell MovementEmbryonic InductionHomeodomain ProteinsReceptor, Platelet-Derived Growth Factor alphaColchicineCulture TechniquesTranscription FactorsDiazepamMolecular Sequence DataEpitheliumNocodazoleCadherinsMicroscopy, ElectronTime FactorsAmino Acid SequenceCell DifferentiationBrainImmunohistochemistrySignal TransductionKineticsVocal CordsModels, MolecularRNA, MessengerProtein FoldingBase SequenceBinding SitesCell LineCells, CulturedMutationRecombinant ProteinsSubstrate SpecificityProtein BindingProtein ConformationEscherichia coliProtein Structure, TertiaryLiverProtein Structure, SecondaryCrystallography, X-RaySequence Homology, Amino AcidDose-Response Relationship, DrugPhonationStructure-Activity RelationshipMutagenesis, Site-DirectedTranscription, GeneticGene Expression RegulationHydrogen-Ion ConcentrationCloning, MolecularSequence AlignmentDNABacterial ProteinsMolecular WeightGene ExpressionTransfectionElectrophoresis, Polyacrylamide GelTumor Cells, CulturedProteinsCatalysisRats, Sprague-DawleyCattlePlasmidsPromoter Regions, GeneticEnzyme ActivationDNA PrimersRabbitsReverse Transcriptase Polymerase Chain ReactionCarrier ProteinsCricetinaeBlotting, Western