Beta-catenin/Tcf-regulated transcription prior to the midblastula transition

Development. 2002 Dec;129(24):5743-52. doi: 10.1242/dev.00150.


Following fertilization, the zygotic genome in many organisms is quiescent until the midblastula transition (MBT), when large-scale transcription begins. In Xenopus embryos, for example, transcription is believed to be repressed until the twelfth cell division. Thus, although dorsal-ventral patterning begins during the first cell cycle, little attention has been given to transcriptional regulation in pre-MBT development. We present evidence that regulated transcription begins during early cleavage stages and that the beta-catenin-Tcf complex is required for the transcription of the Xenopus nodal genes Xnr5 and Xnr6 as early as the 256-cell stage. Moreover, inhibition of beta-catenin/Tcf function can block dorsal development, but only if the inhibition begins early and is maintained throughout pre-MBT stages. Dorsal development can be rescued in ventralized embryos if Tcf-dependent transcription is activated prior to MBT, but activation of Tcf after MBT cannot rescue ventralized embryos, suggesting that beta-catenin/Tcf-dependent transcription is required prior to MBT for dorsal-ventral patterning in Xenopus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blastula / metabolism
  • Cell Division
  • Cytoskeletal Proteins / metabolism
  • Cytoskeletal Proteins / physiology*
  • Embryo, Nonmammalian / physiology*
  • Gene Expression Regulation, Developmental*
  • Genes, Dominant
  • HMGB Proteins / metabolism
  • HMGB Proteins / physiology*
  • Lithium / pharmacology
  • Luciferases / metabolism
  • Nodal Signaling Ligands
  • Phenotype
  • Plasmids / metabolism
  • Protein Biosynthesis
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • TCF Transcription Factors
  • Time Factors
  • Trans-Activators / metabolism
  • Trans-Activators / physiology*
  • Transcription Factor 7-Like 1 Protein
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*
  • Transcription, Genetic
  • Transcriptional Activation
  • Xenopus / embryology*
  • Xenopus Proteins*
  • beta Catenin


  • CTNNB1 protein, Xenopus
  • Cytoskeletal Proteins
  • HMGB Proteins
  • Nodal Signaling Ligands
  • TCF Transcription Factors
  • Trans-Activators
  • Transcription Factor 7-Like 1 Protein
  • Transcription Factors
  • Xenopus Proteins
  • beta Catenin
  • nodal5 protein, Xenopus
  • nodal6 protein, Xenopus
  • Lithium
  • Luciferases