Regulation of Nodal Signalling and Mesendoderm Formation by TARAM-A, a TGFβ-Related Type I Receptor

Aoki, Tazu O.; Mathieu, Juliette; Saint-Etienne, Laure; Rebagliati, Michael; Peyriéras, Nadine; Rosa, Frédéric

doi:10.1006/dbio.2001.0510

Cited by 56 publications

(44 citation statements)

References 55 publications

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“…Interestingly, these sequence motifs also occur in Nodal genes in several mammalian species, including human, raising the possibility of a conserved developmental mechanism (Gore et al, 2005). However, the significance of these findings is currently uncertain because the phenotype of maternal-zygotic sqt mutants resembles that of zygotic sqt mutants (Aoki et al, 2002), suggesting that maternal sqt transcripts are not essential for dorsal specification.…”

Section: Dorsal-ventral Axis Specification By Maternal Transcriptsmentioning

confidence: 99%

Nodal signaling: developmental roles and regulation

2007

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Nodal-related ligands of the transforming growth factor-beta (TGFβ)superfamily play central roles in patterning the early embryo during the induction of mesoderm and endoderm and the specification of left-right asymmetry. Additional roles for this pathway in the maintenance of embryonic stem cell pluripotency and in carcinogenesis have been uncovered more recently. Consistent with its crucial developmental functions, Nodal signaling is tightly regulated by diverse mechanisms including the control of ligand processing, utilization of co-receptors, expression of soluble antagonists, as well as positive- and negative-feedback activities.

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Section: Dorsal-ventral Axis Specification By Maternal Transcriptsmentioning

confidence: 99%

Nodal signaling: developmental roles and regulation

2007

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“…We used a constitutively activated form of Tar*/Acvr1b, a type I receptor for the Nodal factors, to activate Nodal signalling (Aoki et al, 2002b;Peyrieras et al, 1998;Renucci et al, 1996). To block FGF signalling, we used a dominant-negative form of FGFR1 (DN-FGFR1) (Fürthauer et al, 2004).…”

Section: Fgf/erk Signalling Represses Endoderm Formationmentioning

confidence: 99%

Zebrafish endoderm formation is regulated by combinatorial Nodal, FGF and BMP signalling

Poulain¹,

Fürthauer

Thisse

et al. 2006

Development

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In the zebrafish embryo, the mesoderm and endoderm originate from common precursors and segregate during gastrulation by mechanisms that are largely unknown. Understanding how the signalling pathways that regulate endoderm and mesoderm formation interact is crucial to understanding how the germ layers are established. Here, we have analysed how the FGF and BMP pathways interact with Nodal signalling during the process of endoderm formation. We found that activation of the FGF/ERK pathway disrupts endoderm formation in the embryo and antagonizes the ability of an activated form of Tar/Acvr1b to induce endoderm at the animal pole. By contrast, inhibition of FGF signalling increases the number of endodermal precursors and potentiates the ability of Tar*/Acvr1b to induce endoderm at the animal pole. Using a pharmacological inhibitor of the FGF receptor, we show that reducing FGF signalling partially rescues the deficit of endoderm precursors in bon mutant embryos. Furthermore, we found that overexpression of BMPs compromises endoderm formation, suggesting that formation of endoderm precursors is negatively regulated by BMPs on the ventral side. We show that simultaneous inhibition of the FGF/Ras and BMP pathways results in a dramatic increase in the number of endoderm precursors. Taken together, these data strongly suggest that BMP and FGF-ERK pathways cooperate to restrict the number of endodermal progenitors induced in response to Nodal signalling. Finally, we investigated the molecular basis for the FGF-MAPK-dependent repression of endoderm formation. We found that FGF/ERK signalling causes phosphorylation of Casanova/Sox32, an important regulator of endoderm determination, and provide evidence that this phosphorylation attenuates its ability to induce sox17. These results identify a molecular mechanism whereby FGF attenuates Nodal-induced endodermal transcription factors and highlight a potential mechanism whereby mesoderm and endoderm fates could segregate from each other.

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“…Cell transplantations were targeted to the endoderm using either an injection of mRNA encoding the activated Taram-A receptor (tar*), as previously described (Aoki et al, 2002a;Aoki et al, 2002b;David et al, 2002), or cas (sox32) mRNA (Dickmeis et al, 2001). Briefly, wild-type donor embryos were injected at the one-cell stage with a mixture of 2% tetramethylrhodamine-isothiocyanate dextran and 3% lysine-fixable biotin dextran (10,000 M r , Molecular Probes) together with 1 ng cas or 1 pg tar* RNA (cas/dextran or tar*/dextran, respectively).…”

Section: Cell Transplantationmentioning

confidence: 99%

Requirements for endoderm and BMP signaling in sensory neurogenesis in zebrafish

Holzschuh

Wada

et al. 2005

Development

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Cranial sensory neurons largely derive from neurogenic placodes(epibranchial and dorsolateral), which are ectodermal thickenings that form the sensory ganglia associated with cranial nerves, but the molecular mechanisms of placodal development are unclear. Here, we show that the pharyngeal endoderm induces epibranchial neurogenesis in zebrafish, and that BMP signaling plays a crucial role in this process. Using a her5:egfptransgenic line to follow endodermal movements in living embryos, we show that contact between pharyngeal pouches and the surface ectoderm coincides with the onset of neurogenesis in epibranchial placodes. By genetic ablation and reintroduction of endoderm by cell transplantation, we show that these contacts promote neurogenesis. Using a genetic interference approach we further identify bmp2b and bmp5 as crucial components of the endodermal signals that induce epibranchial neurogenesis. Dorsolateral placodes (trigeminal, auditory, vestibular, lateral line) develop independently of the endoderm and BMP signaling, suggesting that these two sets of placodes are under separate genetic control. Our results show that the endoderm regulates the differentiation of cranial sensory ganglia, which coordinates the cranial nerves with the segments that they innervate.

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Regulation of Nodal Signalling and Mesendoderm Formation by TARAM-A, a TGFβ-Related Type I Receptor

Cited by 56 publications

References 55 publications

Nodal signaling: developmental roles and regulation

Nodal signaling: developmental roles and regulation

Zebrafish endoderm formation is regulated by combinatorial Nodal, FGF and BMP signalling

Requirements for endoderm and BMP signaling in sensory neurogenesis in zebrafish

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