Authors:

Callum Newberry

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About Paper:

Wnt signaling drives germ layer (endoderm, mesoderm, and ectoderm) specification and patterning along the anterior-posterior (AP) axis during early embryonic development across metazoans from cnidarians to humans. In sea urchin embryos AP axis formation is controlled by an integrated Wnt signaling network of canonical (Wnt/β-catenin) and non-canonical (Wnt/JNK and Wnt/PKC) pathways. Despite the importance of Wnt signaling in many developmental processes we still have a limited understanding of how these different Wnt signaling cascades interact during embryogenesis in any model system. Our lab has previously shown that non-canonical Wnt/PKC signaling is broadly active during early AP axis specification suggesting that calcium signaling is necessary for AP patterning in the sea urchin, but we still lack a full understanding of the calcium signaling cascade involved in axial patterning. The goal of my research is to examine the role of calcium signaling molecules in embryonic axis formation to assess if the Wnt/calcium signaling cascade is necessary for early embryonic development. We investigated the effects of 3 calcium signaling inhibitors (Calcineurin, CAMKII, and IP3 inhibitors) on sea urchin embryogenesis. In the calcineurin inhibitor the embryos failed to develop mesoderm derived pigment cells. In the CAMKII inhibitor the skeleton did not form, and the gut formed outside of the body. Lastly, in the IP3 inhibitor we saw that both the skeleton and gut did not form. These results suggest that all three molecules are necessary for embryogenesis but may be involved in different Wnt pathways. We used insitu hybridization (WMISH) to examine how two genes involved in axis formation (foxq2 and bmp2/4) were impacted by the CAMKII inhibitor. Our results showed that both genes were downregulated yielding the same phenotype observed in Wnt/PKC inhibition. This suggests the calcium signaling molecule is required for axial patterning in the sea urchin embryo.

Source:

Auburn University / College of Sciences and Mathematics / 2025

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Co-authors:

Callum Newberry