HcN13, a Fibroblast Growth Factor Binding Protein, Is Associated with Shell Formation in Hyriopsis cumingii

Area of Science:

• Marine Biology
• Biochemistry
• Biomineralization

Background:

• Fibroblast growth factor binding proteins (FGF-BPs) are known regulators of FGF signaling in vertebrates.
• Their role in invertebrate biomineralization, particularly in mollusk shell formation, remains largely unexplored.

Purpose of the Study:

• To identify and characterize a novel FGF-BP in the mollusk Hyriopsis cumingii.
• To investigate the function of this protein in shell matrix formation and biomineralization.

Main Methods:

• Gene identification and sequence analysis of HcN13 from Hyriopsis cumingii.
• Quantitative real-time PCR and in situ hybridization for expression analysis.
• In vivo suppression of HcN13 and in vitro crystal formation assays.

Main Results:

• HcN13, a novel FGF-BP family member, is expressed in the mollusk mantle, specifically in nacreous layer-forming cells.
• Suppression of HcN13 led to the destruction of shell prisms and nacre tablets.
• HcN13 expression correlates with both normal and disordered pearl nacre deposition.

Conclusions:

• HcN13 is essential for mollusk shell formation and biomineralization, acting as a modulator of signaling pathways.
• This study reveals the presence and critical function of FGF-BPs in invertebrate biomineralization for the first time.