Extraembryonic signals under the control of MGA, Max, and Smad4 are required for dorsoventral patterning
- Authors
- Sun, Y., Tseng, W.C., Fan, X., Ball, R., and Dougan, S.T.
- ID
- ZDB-PUB-140502-19
- Date
- 2014
- Source
- Developmental Cell 28(3): 322-334 (Journal)
- Registered Authors
- Ball, Rebecca, Dougan, Scott T., Fan, Xiang, Sun, Yuhua, Tseng, Wei-Chia
- Keywords
- none
- MeSH Terms
-
- Body Patterning*
- Zebrafish/genetics
- Zebrafish/growth & development
- Zebrafish/metabolism*
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism*
- RNA, Messenger/genetics
- Smad4 Protein/genetics
- Smad4 Protein/metabolism*
- Immunoenzyme Techniques
- Blotting, Western
- Signal Transduction
- Animals
- Immunoprecipitation
- Real-Time Polymerase Chain Reaction
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/metabolism*
- Gene Expression Regulation, Developmental
- Regulatory Elements, Transcriptional
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism*
- Bone Morphogenetic Protein 2/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- PubMed
- 24525188 Full text @ Dev. Cell
In vertebrates, extraembryonic tissues can act as signaling centers that impose a reproducible pattern of cell types upon the embryo. Here, we show that the zebrafish yolk syncytial layer (YSL) secretes a ventralizing signal during gastrulation. This activity is mediated by Bmp2b/Swirl (Swr) expressed under the control of Max?s giant associated protein (MGA) and its binding partners, Max and Smad4. MGA coimmunoprecipitates with both Max and Smad4 in embryo extracts, and the three proteins form a complex in vitro. Furthermore, all three proteins bind to a DNA fragment upstream of the bmp2b transcription start site. Targeted depletion of MGA, its binding partners, or Bmp2b/Swr from the YSL reduces BMP signaling throughout the embryo, resulting in a mildly dorsalized phenotype. We conclude that MGA, Max, and Smad4 act in the extraembryonic YSL to initiate a positive feedback loop of Bmp signaling within the embryo.