Abstract
In early Xenopus embryos, the prototypical XFast-1/Smad2/Smad4 complex ARF1 is induced at the Mix.2 ARE by activin overexpression. We have characterised ARF2, a related, but much more abundant, complex formed during gastrulation in response to endogenous TGFbeta family members and we have identified a novel Fast family member, XFast-3, as its transcription factor component. Endogenous ARF2 efficiently competes out ARF1 at early gastrulation, due to the ability of XFast-3 to interact with activated Smads with much higher affinity than XFast-1. We demonstrate that ARF1 and ARF2 are activated by distinct TGFbeta family members. Using morpholino antisense oligonucleotides to deplete levels of the constituent transcription factors XFast-1 and XFast-3 specifically, we demonstrate an important role for ARF1 and ARF2 in early Xenopus embryos in controlling the convergent extension movements of gastrulation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells
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ADP-Ribosylation Factor 1 / metabolism
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ADP-Ribosylation Factors / genetics
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Amino Acid Sequence
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Animals
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Binding, Competitive
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Embryo, Nonmammalian
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Female
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Forkhead Transcription Factors
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Gastrula*
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Gene Expression Regulation, Developmental
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Growth Substances / genetics
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Growth Substances / metabolism
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Intercellular Signaling Peptides and Proteins*
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Mice
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Molecular Sequence Data
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Nerve Growth Factors
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Oligonucleotides, Antisense / genetics
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Response Elements
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Saccharomyces cerevisiae Proteins*
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Sequence Homology, Amino Acid
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Smad Proteins
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Smad2 Protein
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Smad4 Protein
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T-Box Domain Proteins / genetics
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T-Box Domain Proteins / metabolism
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Trans-Activators / genetics
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Trans-Activators / metabolism*
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Transcription Factors / genetics*
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Transcription Factors / metabolism*
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Xenopus / embryology*
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Xenopus / metabolism
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Xenopus Proteins / genetics*
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Xenopus Proteins / metabolism
Substances
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DNA-Binding Proteins
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FOXH1 protein, Xenopus
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Forkhead Transcription Factors
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Foxh1 protein, mouse
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GDF3 protein, Xenopus
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Growth Substances
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Intercellular Signaling Peptides and Proteins
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Nerve Growth Factors
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Oligonucleotides, Antisense
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Saccharomyces cerevisiae Proteins
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Smad Proteins
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Smad2 Protein
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Smad2 protein, Xenopus
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Smad2 protein, mouse
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Smad4 Protein
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Smad4 protein, mouse
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T-Box Domain Proteins
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Trans-Activators
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Transcription Factors
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VegT protein, Xenopus
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Xenopus Proteins
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foxh1.2 protein, Xenopus
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smad4.1 protein, Xenopus
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smad4.2 protein, Xenopus
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ARF2 protein, S cerevisiae
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Arf2 protein, mouse
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ADP-Ribosylation Factor 1
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ADP-Ribosylation Factors