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The beta-cateninVegT-regulated early zyg ... irect target of SOX3 regulation
The beta-catenin/VegT-regulated early zygotic gene Xnr5 is a direct target of SOX3 regulation.
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In Xenopus laevis, beta-catenin-mediated dorsal axis formation can be suppressed by overexpression of the HMG-box transcription factor XSOX3. Mutational analysis indicates that this effect is due not to the binding of XSOX3 to beta-catenin nor to its competition with beta-catenin-regulated TCF-type transcription factors for specific DNA binding sites, but rather to SOX3 binding to sites within the promoter of the early VegT- and beta-catenin-regulated dorsal-mesoderm-inducing gene Xnr5. Although B1-type SOX proteins, such as XSOX3, are commonly thought to act as transcriptional activators, XSOX3 acts as a transcriptional repressor of Xnr5 in both the intact embryo and animal caps injected with VegT RNA. Expression of a chimeric polypeptide composed of XSOX3 and a VP16 transcriptional activation domain or morpholino-induced decrease in endogenous XSOX3 polypeptide levels lead to an increase in Xnr5 expression, as does injection of an anti-XSOX3 antibody that inhibits XSOX3 DNA binding. These observations indicate that maternal XSOX3 acts in a novel manner to restrict Xnr5 expression to the vegetal hemisphere.
Zhang C, Basta T, Jensen ED, Klymkowsky MW
Development (Cambridge, England)
2003-12-01 00:00
130
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5609-24
Amino Acid Sequence,Animals,Antibodies,Base Sequence,Body Patterning,Cytoskeletal Proteins,DNA-Binding Proteins,Female,Gene Expression Regulation, Developmental,Genes, Reporter,Hela Cells,High Mobility Group Proteins,Homeodomain Proteins,Humans,Models, Molecular,Molecular Sequence Data,Nuclear Proteins,Oligonucleotides, Antisense,Oocytes,Promoter Regions (Genetics),Protein Structure, Tertiary,Proteins,T-Box Domain Proteins,Trans-Activators,Transcription Factors,Xenopus Proteins,Xenopus laevis,beta Catenin,Antibodies,CTNNB1 protein, human,Cytoskeletal Proteins,DNA-Binding Proteins,High Mobility Group Proteins,Homeodomain Proteins,Nuclear Proteins,Oligonucleotides, Antisense,Proteins,Sox3 protein,T-Box Domain Proteins,Trans-Activators,Transcription Factors,VegT protein, Xenopus,Xenopus Proteins,Xnr5 protein, Xenopus,beta Catenin,beta-catenin protein, Xenopus,siamois protein, Xenopus
Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
Development
NIGMS GM54001
0950-1991
10.1242/dev.00798
dev.00798
640
True
14522872
