title: Expression of chick Tbx-2, Tbx-3, and Tbx-5 genes during early heart development: evidence for BMP2 induction of Tbx2.
abstract: Expression patterns of Tbx2, -3, and -5 genes were analyzed during chick embryonic heart development. Transcripts of these three cTbx genes were detected in overlapping patterns in the early cardiac crescent. cTbx2 and cTbx3 expression patterns closely overlapped with that of bmp2. cTbx5 expression diverged from cTbx2 and bmp2 during the elaboration and folding of the heart tube. In comparison, cTbx2 expression overlapped significantly with that of bmp2 and bmp4 during all stages of heart development and during later embryonic stages, suggestive of a specialized role for Tbx2 in septation. Coexpression of cTbx 2 and cTbx3 genes with bmp2 transcripts raised the possibility that these cTbx genes might be downstream bmp2 targets. Application of bmp2 selectively induced cTbx2 and cTbx3 expression in noncardiogenic embryonic tissue, and the bmp antagonist Noggin down-regulated cTbx2 gene activity. Moreover, the appearance of murine mTbx2 was blocked in bmp2 null mouse embryos. cTbx2 and to a lesser extent cTbx3 gene activity appears to be directed by BMPs during early cardiogenesis.
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA.
authors.forename: M
authors.initials: M
authors.lastname: Yamada
authors.forename: J P
authors.initials: JP
authors.lastname: Revelli
authors.forename: G
authors.initials: G
authors.lastname: Eichele
authors.forename: M
authors.initials: M
authors.lastname: Barron
authors.forename: R J
authors.initials: RJ
authors.lastname: Schwartz
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D017353:Gene Deletion; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics*; D006321:Heart / Q000196:embryology*; D017403:In Situ Hybridization; D051379:Mice; D018345:Mice, Knockout; D009024:Morphogenesis; D009206:Myocardium / Q000378:metabolism; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism; D016212:Transforming Growth Factor beta
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; D016212:Transforming Growth Factor beta