Frizzled3 expression and colony development in hydractiniid hydrozoans

Area of Science:

• Developmental Biology
• Evolutionary Biology
• Molecular Biology

Background:

• Hydractiniid hydrozoan colonies exhibit diverse forms, including stolonal mats and free stolons, integrated by shared gastrovascular systems.
• While polyp development is understood, the signaling pathways governing colonial patterning remain largely unknown.
• The Wnt signaling pathway is a conserved pathway involved in various developmental processes.

Purpose of the Study:

• To investigate the role of the Wnt receptor family, Frizzled, in the patterning of hydractiniid hydrozoan colonies.
• To understand the evolutionary implications of Frizzled gene family members in hydrozoan colony formation and loss.

Main Methods:

• Phylogenetic analysis of the Frizzled gene family in hydrozoans.
• Spatial expression pattern analysis of Frizzled genes in Hydractinia symbiolongicarpus and Podocoryna carnea.
• Comparative genomic analysis, including the examination of Frizzled genes in the solitary hydrozoan Hydra.

Main Results:

• Hydrozoans possess four Frizzled orthologs.
• Frizzled3 exhibits spatially restricted expression in colony-specific tissues of Hydractinia and Podocoryna, correlating with their distinct colony morphologies.
• Frizzled3 is absent in the genome of Hydra, a solitary hydrozoan.

Conclusions:

• The Wnt signaling pathway, particularly Frizzled3, plays a significant role in establishing and diversifying colonial architectures in hydrozoans.
• The differential presence and expression of Frizzled3 suggest its involvement in the evolution of coloniality and the loss thereof in Hydrozoa.