title: Coordinate involvement of Nodal-dependent inhibition and Wnt-dependent activation in the maintenance of organizer-specific bmp2b in zebrafish.
abstract: A vertebrate signaling center, known in zebrafish as the organizer, is essential for axis patterning and formation and is regulated by multiple cell signaling pathways, including Wnt, Nodal, and Bmp. Organizer-specific Bmp2b plays important roles in the maintenance of the Bmp activity gradient and dorsal-ventral patterning. However, it is unknown how transcription of bmp2b in the organizer is regulated. In this study, we generated a bmp2b transgenic line Tsg(-2.272bmp2b:gfp) that reproduced organizer-specific bmp2b expression. Dissection analysis revealed that a 0.273-kb minimal promoter was indispensable for bmp2b expression in the dorsal organizer. Reporter assays showed that organizer-specific bmp2b is negatively regulated by the Nodal signal and positively regulated by the Wnt signal in both embryos and cell lines. Promoter analysis and chromatin-immunoprecipitation (ChIP) indicated that one consensus Smad-binding element (SBE) (CAGAC) and one Lef/Tcf-binding element (LBE) (AGATAA) were present in the 0.273-kb promoter, and could be directly bound by Smad2 and β-catenin proteins. Together, these results suggest that maintenance of organizer-specific bmp2b expression involves opposite and concerted regulation by Nodal and Wnt signaling.
authors.affiliation: The Engineering Technological Center of Mushroom Industry, Minnan Normal University, Zhangzhou, Fujian, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xue
authors.forename: Cencan
authors.initials: C
authors.lastname: Xing
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Zhang
authors.forename: Canbin
authors.initials: C
authors.lastname: Chen
authors.forename: Jingjin
authors.initials: J
authors.lastname: Xu
authors.forename: Anming
authors.initials: A
authors.lastname: Meng
authors.forename: Yutian
authors.initials: Y
authors.lastname: Pan
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001665:Binding Sites / Q000235:genetics; D019521:Body Patterning / Q000235:genetics; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D057809:HEK293 Cells; D006801:Humans; D017403:In Situ Hybridization; D055457:Nodal Protein / Q000235:genetics* / Q000378:metabolism; D020897:Organizers, Embryonic / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D051899:Smad2 Protein / Q000378:metabolism; D060449:Wnt Signaling Pathway / Q000235:genetics*; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D055396:Bone Morphogenetic Protein 2; D055457:Nodal Protein; D051899:Smad2 Protein; D029961:Zebrafish Proteins; D051176:beta Catenin; C405936:bmp2b protein, zebrafish; C497786:smad2 protein, zebrafish