Transcription Factor TFIIIARNA, Ribosomal, 5STranscription FactorsXenopus laevisRNA, RibosomalTranscription, GeneticDNA-Binding ProteinsPromoter Regions, GeneticMolecular Sequence DataBase SequenceSp1 Transcription FactorGene Expression RegulationBinding SitesZinc FingersProtein BindingTranscriptional ActivationTrans-ActivatorsRNA, MessengerDNABasic Helix-Loop-Helix Transcription FactorsAmino Acid SequenceNuclear ProteinsTranscription Factor AP-1Repressor ProteinsCell LineForkhead Transcription FactorsHomeodomain ProteinsGene Expression Regulation, DevelopmentalSignal TransductionMutationBasic-Leucine Zipper Transcription FactorsCell NucleusTranscription Factor AP-2Cell DifferentiationXenopusTransfection