AI Article Synopsis
- The trunk is a significant aspect of the bilaterian body plan, with diverse anatomical variations, primarily studied in segmented animals like arthropods and chordates.
- This study focuses on unsegmented animals to explore mechanisms of posterior axis elongation (PAE) separate from segmentation, particularly examining the roles of Wnt and Notch signaling pathways in hemichordates.
- Findings suggest a Wnt-Brachyury feedback loop during PAE, indicating that this interaction is an ancestral trait in deuterostomes, contributing to understanding bilaterian trunk evolution.
Article Abstract
The trunk is a key feature of the bilaterian body plan. Despite spectacular morphological diversity in bilaterian trunk anatomies, most insights into trunk development are from segmented taxa, namely arthropods and chordates. Mechanisms of posterior axis elongation (PAE) and segmentation are tightly coupled in arthropods and vertebrates, making it challenging to differentiate between the underlying developmental mechanisms specific to each process. Investigating trunk elongation in unsegmented animals facilitates examination of mechanisms specific to PAE and provides a different perspective for testing hypotheses of bilaterian trunk evolution. Here we investigate the developmental roles of canonical Wnt and Notch signaling in the hemichordate and reveal that both pathways play key roles in PAE immediately following the completion of gastrulation. Furthermore, our functional analysis of the role of Brachyury is supportive of a Wnt-Brachyury feedback loop during PAE in , establishing this key regulatory interaction as an ancestral feature of deuterostomes. Together, our results provide valuable data for testing hypotheses of bilaterian trunk evolution.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6486776 | PMC |
| http://dx.doi.org/10.1073/pnas.1817496116 | DOI Listing |
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