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Lef/Tcf-dependent Wnt/beta-catenin signaling during Xenopus axis specification
Xin Geng1, Lei Xiao, Gu Fa Lin
1Laboratory of Molecular and Cell Biology, Laboratory of Stem Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Yue-yang Road 320, 200031, Shanghai, PR China
FEBS Letters
|July 16, 2003
Summary
Wnt/beta-catenin signaling in Xenopus development does not always activate Lef/Tcf transcription factors. Zygotic Lef/Tcf activity is crucial for ventroposterior development, mediated by Wnt-8 signaling.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- The Wnt/beta-catenin signaling pathway is vital for Xenopus axis specification.
- The precise role of Lef/Tcf transcription factors in this pathway's developmental functions is not fully understood.
Purpose of the Study:
- To investigate whether Wnt/beta-catenin signaling exclusively utilizes Lef/Tcf transcription factors during Xenopus axis specification.
- To determine the necessity of Lef/Tcf activity for early Xenopus embryonic development.
Main Methods:
- Generation of transgenic Xenopus embryos expressing GFP under a Lef/Tcf-dependent promoter sensitive to Wnt/beta-catenin activity.
- Analysis of GFP expression patterns in early development.
- Ubiquitous expression of dominant Lef-1 protein variants in transgenic embryos.
Main Results:
- Unexpectedly, Wnt/beta-catenin activity did not consistently lead to Lef/Tcf-dependent gene activation in all known signaling territories.
- Zygotic Lef/Tcf activity was found to be essential for ventroposterior development in Xenopus embryos.
- Wnt-8 signaling's ventroposteriorizing effect is dependent on Lef/Tcf proteins.
Conclusions:
- Endogenous Wnt/beta-catenin activity does not invariably trigger Lef/Tcf-dependent gene expression.
- Zygotic Wnt-8 signaling mediates its ventroposteriorizing effects through Lef/Tcf transcription factors during Xenopus development.