The Fraser complex interconnects tissue layers to support basal epidermis and osteoblast integrated morphogenesis...

Area of Science:

• Developmental Biology
• Genetics
• Regenerative Medicine

Background:

• Fraser Syndrome is a rare genetic disorder affecting epithelial-mesenchymal associations, leading to variable organ defects, including limb malformations.
• The precise developmental origins of digit malformations in Fraser Syndrome remain unclear.
• The Fraser Complex, including Fras1 and Frem2, plays a role in these associations.

Approach:

• Zebrafish fras1 mutants were analyzed to model Fraser Syndrome-associated skeletal defects.
• Fin development and regeneration in mutants were studied using morphological, cellular, and molecular techniques.
• Single-cell RNA-Seq, in situ hybridization, and antibody staining elucidated gene expression and protein localization.

Key Points:

• Zebrafish fras1 mutants exhibit significant fin abnormalities, including bone fusions and disrupted symmetry, during development and regeneration.
• Fraser Complex components are localized to the basal epidermis during fin regeneration.
• Loss of Fras1 leads to epidermal blistering and disorganized basal epidermis and osteoblasts, despite intact Sonic hedgehog signaling.

Conclusions:

• The Fraser Complex is essential for tissue layer adhesion, supporting integrated morphogenesis between the basal epidermis and osteoblasts.
• Zebrafish fin regeneration provides a tractable model for studying Fraser Syndrome-related digit defects and epithelial-mesenchymal interactions.