Regulation of dharma/bozozok by the Wnt pathway.
The zebrafish homeobox gene dharma/bozozok (boz) is required for the formation and/or function of the Nieuwkoop center and the subsequent induction of the Spemann organizer. dharma is expressed soon after the midblastula transition in the dorsal blastomeres and the dorsal yolk syncytial layer (YSL). We found that the expression of dharma was upregulated or ectopically induced by misexpression of a Wnt protein and cytoplasmic components of the Wnt signaling pathway and downregulated by the expression of dominant-negative Tcf3. A 1.4-kbp fragment of the dharma promoter region contains consensus sequences for Tcf/Lef binding sites. This promoter region recapitulated the Wnt-dependent and dorsal dharma expression pattern when it was fused to luciferase or GFP. Deletion and point mutant analyses revealed that the Tcf/Lef binding sites were required to drive this expression pattern. These data established that dharma/boz functions between the dorsal determinants-mediated Wnt signals and the formation of the Nieuwkoop center.
Division of Molecular Oncology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
S L
SL
Ryu
R
R
Fujii
Y
Y
Yamanaka
T
T
Shimizu
T
T
Yabe
T
T
Hirata
M
M
Hibi
T
T
Hirano
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003593:Cytoplasm / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D017931:DNA Primers / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D015723:Gene Library; D005799:Genes, Dominant; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D024002:HMGB Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D008156:Luciferases / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D051821:Lymphoid Enhancer-Binding Factor 1; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D055457:Nodal Protein; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D051820:TCF Transcription Factors; D013997:Time Factors; D015534:Trans-Activators; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism; D015854:Up-Regulation; D051153:Wnt Proteins; D015027:Zebrafish; D029961:Zebrafish Proteins; D051176:beta Catenin
D003598:Cytoskeletal Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D024002:HMGB Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D055457:Nodal Protein; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D051820:TCF Transcription Factors; D015534:Trans-Activators; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; C495269:ctnnb1 protein, zebrafish; C113874:dharma protein, zebrafish; C094522:wnt8b protein, zebrafish; D049452:Green Fluorescent Proteins; D012313:RNA; D004247:DNA; D008156:Luciferases