Smad4 controls signaling robustness and morphogenesis by differentially contributing to the Nodal and BMP pathways.
Luca GuglielmiClaire HeliotSunil KumarYuriy AlexandrovIlaria GoriFoteini PapaleonidopoulouChristopher BarringtonPhilip EastAndrew D EconomouPaul M W FrenchJames McGintyCaroline S HillPublished in: Nature communications (2021)
The transcriptional effector SMAD4 is a core component of the TGF-β family signaling pathways. However, its role in vertebrate embryo development remains unresolved. To address this, we deleted Smad4 in zebrafish and investigated the consequences of this on signaling by the TGF-β family morphogens, BMPs and Nodal. We demonstrate that in the absence of Smad4, dorsal/ventral embryo patterning is disrupted due to the loss of BMP signaling. However, unexpectedly, Nodal signaling is maintained, but lacks robustness. This Smad4-independent Nodal signaling is sufficient for mesoderm specification, but not for optimal endoderm specification. Furthermore, using Optical Projection Tomography in combination with 3D embryo morphometry, we have generated a BMP morphospace and demonstrate that Smad4 mutants are morphologically indistinguishable from embryos in which BMP signaling has been genetically/pharmacologically perturbed. Smad4 is thus differentially required for signaling by different TGF-β family ligands, which has implications for diseases where Smad4 is mutated or deleted.
Keyphrases
- transforming growth factor
- epithelial mesenchymal transition
- mesenchymal stem cells
- lymph node
- magnetic resonance imaging
- transcription factor
- signaling pathway
- squamous cell carcinoma
- spinal cord
- computed tomography
- radiation therapy
- magnetic resonance
- immune response
- resting state
- dendritic cells
- bone marrow
- neoadjuvant chemotherapy
- high speed
- bone regeneration
- cell fate