Multiple signaling pathways control Tbx6 expression during Xenopus myogenesis.
Tbx6 is critical for somite specification and myogenesis initiation. It has been shown that Activin/Nodal, VegT/Nodal, FGF, and BMP signaling pathways are involved early in specifying mesoderm or later in patterning mesoderm, and Xnot plays roles in setting up the boundary between notochord and paraxial mesoderm. In this study, we introduce the dominant negative form of above genes into embryos to evaluate if they are responsible for regulating Tbx6 expression. The results show that: (1) Activin/Nodal and VegT/Nodal signals are necessary for both initiation and maintenance of Tbx6 expression, and Nodal is sufficient to induce ectopic Tbx6 expression; (2) FGF signal is necessary for the initiation and maintenance of Tbx6, but it is not sufficient to induce Tbx6 expression; (3) BMP is also necessary for the expression of Tbx6, and the induction of Tbx6 expression by BMP is dose dependent; (4) Xnot has no effect on the expression of Tbx6. Our results suggest that several signaling pathways are involved in regulating Tbx6 expression, and pave the route to reveal the molecular mechanism of initiating myogenesis.
Fang
Pan-Feng
PF
Laboratory of Molecular and Cell Biology, and Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China.
Hu
Rui-Ying
RY
He
Xing-Yue
XY
Ding
Xiao-Yan
XY
D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005346:Fibroblast Growth Factors / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005799:Genes, Dominant; D017403:In Situ Hybridization; D008648:Mesoderm / Q000378:metabolism; D055457:Nodal Protein; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D020825:T-Box Domain Proteins; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D029867:Xenopus Proteins / Q000737:chemistry / Q000502:physiology*; D014982:Xenopus laevis
D019485:Bone Morphogenetic Proteins; D055457:Nodal Protein; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; C491181:Tbx6 protein, Xenopus; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; D005346:Fibroblast Growth Factors