GastrulaBlastulaEmbryo, NonmammalianXenopus ProteinsEctodermEmbryonic InductionGoosecoid ProteinOrganizers, EmbryonicMesodermPleurodelesXenopusSea UrchinsXenopus laevisGene Expression Regulation, DevelopmentalBody PatterningZebrafishGastrulationNervous SystemEndodermBlastocystIn Situ HybridizationZebrafish ProteinsTriturusFetal ProteinsBlastomeresBone Morphogenetic ProteinsMorphogenesisBlastodermHomeodomain ProteinsOtx Transcription FactorsT-Box Domain ProteinsNotochordMicroinjectionsBone Morphogenetic Protein 4Molecular Sequence DataGenes, HomeoboxTranscription FactorsFibroblast Growth FactorsAmino Acid SequenceNodal ProteinActivinsBase SequenceRNA, MessengerSignal TransductionNodal Signaling LigandsEchinodermataCloning, MolecularCell DifferentiationSequence Homology, Amino AcidGerm LayersDNA-Binding ProteinsProteinsStrongylocentrotus purpuratusTrans-ActivatorsOvumZygoteRepressor ProteinsSOXF Transcription FactorsEmbryonic DevelopmentHemicentrotusInhibinsTime FactorsTranscription Factor 3StarfishLarvaRanidaeCell LineageDNA, ComplementaryCentral Nervous SystemCleavage Stage, OvumUrochordataKillifishesAnuraIntercellular Signaling Peptides and ProteinsTransforming Growth Factor betaBenzoylarginine NitroanilidePrimitive StreakParacentrotusbeta CateninTissue TransplantationTranscription, GeneticChordataEmbryologyMicroscopy, Electron, ScanningSomitesCell MovementGlycoproteinsTailChordata, NonvertebrateOogenesisChick EmbryoAnimals, Genetically ModifiedGene ExpressionOocytesDNA PrimersRNASalamandridaeModels, BiologicalGenesNeural Plate