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Updated: Jun 20, 2026
07:34
The Power of Simplicity: Sea Urchin Embryos as in Vivo Developmental Models for Studying Complex Cell-to-cell Signaling Network Interactions
Published on: February 16, 2017
An evolutionary transition of Vasa regulation in echinoderms
Celina E Juliano1, Gary M Wessel
1Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA.
Evolution & Development
|September 17, 2009
Summary
Vasa protein regulation in sea urchins and sea stars reveals evolutionary shifts in development. This DEAD box helicase is crucial for germline and multipotent cells, with its expression timing adapting during echinoderm evolution.
Area of Science:
- Developmental Biology
- Evolutionary Biology
- Molecular Biology
Background:
- Vasa, a DEAD box helicase, is a known germline marker with potential roles in multipotent cells.
- In sea urchins, Vasa protein is enriched in small micromeres, a lineage arising from early asymmetric cell divisions.
- Micromere formation via asymmetric cleavage is a derived trait in echinoderms.
Purpose of the Study:
- To investigate the evolutionary regulation of Vasa in key echinoderms.
- To understand how Vasa regulation relates to the evolution of micromere lineages.
- To explore the conserved role of Vasa in undifferentiated cells during embryogenesis.
Main Methods:
- Comparative analysis of vasa mRNA and protein expression patterns across different echinoderm species (sea urchins and sea stars).
- Examination of Vasa localization during early embryonic development, focusing on micromere and coelomic pouch formation.
- Observation of phenotypic changes in sea urchin embryos upon removal of Vasa-positive micromeres.
Main Results:
- Striking similarities in vasa mRNA expression were observed between sea urchins and sea stars.
- Significant differences in the timing of Vasa protein enrichment were found between sea urchins and sea stars.
- Vasa protein and/or mRNA is consistently enriched in larval coelomic pouches across tested echinoderms.
- Removal of Vasa-positive micromeres in sea urchins led to a reversion to a basal Vasa regulation mechanism seen in sea stars.
Conclusions:
- A conserved Vasa regulatory mechanism was shifted earlier in sea urchin embryogenesis with the evolution of micromeres.
- Vasa plays a conserved role in undifferentiated multipotent cells, specifically in structures like larval coelomic pouches, which are sites of adult rudiment formation.
- The study provides insights into the evolutionary adaptation of Vasa regulation linked to developmental innovations in echinoderms.
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