Temporal and spatial expression of fgfbp genes in zebrafish

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Fibroblast Growth Factor Binding Proteins (FGFBPs) are secreted proteoglycans that act as extracellular chaperones for FGFs, enhancing FGF signaling.
• While three human FGFBP genes are known, and one zebrafish orthologue (fgfbp1a) has been studied, the full FGFBP family in zebrafish remains largely uncharacterized.

Purpose of the Study:

• To clone and characterize the expression patterns of novel FGFBP orthologues in zebrafish.
• To establish a foundation for investigating the roles of the FGFBP family in vertebrates.

Main Methods:

• Cloning of four novel FGFBP orthologues in zebrafish: fgfbp1b, fgfbp2a, fgfbp2b, and fgfbp3.
• Quantitative PCR (qPCR) to analyze transcript levels.
• Whole-mount in situ hybridization (WISH) to determine spatial and temporal expression patterns.

Main Results:

• All identified FGFBP transcripts, except fgfbp2a, exhibit maternal expression.
• fgfbp1b, fgfbp2b, and fgfbp2a show broad expression in the head at 24 hours post-fertilization (hpf), later localizing to pharyngeal tissue, pectoral fins, and liver, respectively.
• fgfbp3 is highly expressed in the central nervous system (CNS) during embryonic and larval stages, and in adult muscle and heart.

Conclusions:

• The study successfully identified and characterized four new FGFBP genes in zebrafish, revealing diverse expression profiles.
• These findings highlight tissue-specific expression patterns of the FGFBP family in adult zebrafish, particularly fgfbp3 in muscle and heart.
• This work serves as a crucial starting point for exploring the functions of FGFBP family genes and their FGF-dependent and -independent mechanisms in vertebrates.