title: Xenopus Brachyury regulates mesodermal expression of Zic3, a gene controlling left-right asymmetry.
abstract: The Brachyury gene has a critical role in the formation of posterior mesoderm and notochord in vertebrate development. A recent study showed that Brachyury is also responsible for the formation of the left-right (L-R) axis in mouse and zebrafish. However, the role of Brachyury in L-R axis specification is still elusive. Here, it is demonstrated that Brachyury is involved in L-R specification of the Xenopus laevis embryo and regulates expression of Zic3, which controls the L-R specification process. Overexpression of Xenopus Brachyury (Xbra) and dominant-negative type Xbra (Xbra-EnR) altered the orientation of heart and gut looping, concomitant with disturbed laterality of nodal-related 1 (Xnr1) and Pitx2 expression, both of which are normally expressed in the left lateral plate mesoderm. Furthermore, activation of inducible type Xbra (Xbra-GR) induces Zic3 expression within 20 min. These results suggest that a role of Brachyury in L-R specification may be the direct regulation of Zic3 expression.
authors.affiliation: Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kitaguchi
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Mizugishi
authors.forename: Minoru
authors.initials: M
authors.lastname: Hatayama
authors.forename: Jun
authors.initials: J
authors.lastname: Aruga
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D005260:Female; D005326:Fetal Proteins; D005775:Gastrula / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D008648:Mesoderm / Q000502:physiology; D009687:Nuclear Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020825:T-Box Domain Proteins / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000502:physiology; D014981:Xenopus; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000097577:Homeobox Protein PITX2; D000098908:Brachyury Protein
chemical_list: D005326:Fetal Proteins; D018398:Homeodomain Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D020825:T-Box Domain Proteins; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000097577:Homeobox Protein PITX2; D000098908:Brachyury Protein; C109036:Zic3 protein, Xenopus; C512832:ndr2 protein, zebrafish; C512833:nodal1 protein, Xenopus