Organizers, EmbryonicGoosecoid ProteinXenopus ProteinsGastrulaEmbryonic InductionNucleolus Organizer RegionXenopusBody PatterningMesodermXenopus laevisEmbryo, NonmammalianGene Expression Regulation, DevelopmentalNodal ProteinIntercellular Signaling Peptides and ProteinsEctodermZebrafish ProteinsHomeodomain ProteinsBone Morphogenetic ProteinsIn Situ HybridizationBone Morphogenetic Protein 4Wnt ProteinsActivinsProteinsMorphogenesisEmbryologyMicroinjectionsTransforming Growth Factor betaGlycoproteinsT-Box Domain ProteinsMolecular Sequence DataSignal TransductionTranscription FactorsAmino Acid SequenceRepressor ProteinsSilver StainingSequence Homology, Amino AcidCarrier ProteinsAmphibiansRNA, MessengerBase SequenceNervous SystemOtx Transcription FactorsGenes, HomeoboxFibroblast Growth Factor 8InhibinsRhombencephalonNotochordHydraMesencephalonAxisNodal Signaling LigandsZebrafishBone Morphogenetic Protein 7HeadTissue TransplantationLIM-Homeodomain ProteinsSilverCell NucleolusCytoskeletal ProteinsWnt1 ProteinTrans-ActivatorsLeft-Right Determination FactorsEndodermDNA-Binding ProteinsMetencephalonBlastulaFetal ProteinsTwins, ConjoinedFibroblast Growth Factors