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Pinhead signaling regulates mesoderm heterogeneity via the FGF receptor-dependent pathway.

ABSTRACT: Among the three embryonic germ layers, the mesoderm plays a central role in the establishment of the vertebrate body plan. The mesoderm is specified by secreted signaling proteins from the FGF, Nodal, BMP and Wnt families. No new classes of extracellular mesoderm-inducing factors have been identified in more than two decades. Here, we show that the pinhead (pnhd) gene encodes a secreted protein that is essential for the activation of a subset of mesodermal markers in the Xenopus embryo. RNA sequencing revealed that many transcriptional targets of Pnhd are shared with those of the FGF pathway. Pnhd activity was accompanied by Erk phosphorylation and required FGF and Nodal but not Wnt signaling. We propose that during gastrulation Pnhd acts in the marginal zone to contribute to mesoderm heterogeneity via an FGF receptor-dependent positive feedback mechanism.

SUBMITTER: Ossipova O

PROVIDER: S-EPMC7502591 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Specification of embryonic mesoderm by Pinhead signaling

Project description:Among the three embryonic germ layers, mesoderm plays a central role in the establishment of the vertebrate body plan. Mesoderm is specified by secreted signaling proteins from the FGF, Nodal, BMP and Wnt families. No new classes of extracellular mesoderm-inducing factors have been identified in more than two decades. Here we show that the Xenopus pinhead (pnhd) gene encodes a novel secreted protein that activates specific mesodermal markers in presumptive ectoderm. We demonstrate that Pnhd is required for the specification of a subset of embryonic mesoderm in vivo. RNA sequencing revealed that many transcriptional targets of Pnhd are shared with those of the FGF pathway. Pnhd signaling involves active FGF but not Wnt receptors and is accompanied by Erk1 phosphorylation. We propose that Pnhd operates in the marginal zone to specify mesodermal progenitors via an FGF receptor-dependent mechanism.

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