Organizers, EmbryonicNucleolus Organizer RegionCell DifferentiationEmbryonic DevelopmentGene Expression Regulation, DevelopmentalGoosecoid ProteinEmbryo, NonmammalianBody PatterningGastrulaXenopus ProteinsEmbryonic InductionHomeodomain ProteinsEmbryo, MammalianTranscription FactorsMesodermIn Situ HybridizationSignal TransductionZebrafish ProteinsZebrafishMolecular Sequence DataSilver StainingCells, CulturedMorphogenesisXenopusCell LineageEmbryologyStem CellsEmbryonic Stem CellsRNA, MessengerEmbryonic and Fetal DevelopmentBlastocystChick EmbryoBone Morphogenetic ProteinsWnt ProteinsBase SequenceCell LineDNA-Binding ProteinsXenopus laevisEctodermEndodermOtx Transcription FactorsNervous SystemNotochordAmino Acid SequenceGene Expression RegulationCell DivisionPhenotypeMice, KnockoutIntercellular Signaling Peptides and ProteinsTretinoinRepressor ProteinsFibroblast Growth Factor 8Trans-ActivatorsRhombencephalonMice, Inbred C57BLReverse Transcriptase Polymerase Chain ReactionNodal ProteinCell ProliferationMice, TransgenicTranscription, GeneticImmunohistochemistryMutationBlastulaHydraModels, BiologicalMesencephalonGene ExpressionProteinsGenes, HomeoboxActivinsTime FactorsNuclear ProteinsLIM-Homeodomain ProteinsFetal ProteinsHeadT-Box Domain ProteinsTransforming Growth Factor betaBlastomeresbeta CateninDrosophila ProteinsNodal Signaling LigandsPromoter Regions, GeneticZygotePregnancyDNA PrimersCell CycleGene Expression ProfilingOocytesTissue TransplantationAxisNerve Tissue ProteinsDrosophilaBone Morphogenetic Protein 4Sequence Homology, Amino AcidQuailFibroblast Growth FactorsCell MovementCloning, MolecularMembrane ProteinsHedgehog Proteins