Engineering an fgfr4 knockout zebrafish to study its role in development and disease

Area of Science:

• Genetics and Developmental Biology
• Cancer Research
• Molecular Biology

Background:

• Fibroblast growth factor receptor 4 (FGFR4) is implicated in lipid metabolism, tissue repair, and vertebrate development.
• FGFR4 overexpression and mutations are linked to various adult and pediatric cancers, presenting a therapeutic target.

Approach:

• Generated three alleles of fgfr4 knockout zebrafish using CRISPR/Cas9 gene editing technology.
• Injected single-cell zebrafish embryos with fgfr4 targeting guide RNA and Cas9, creating mutant lines through outcrossing.
• Confirmed successful gene knockout by assessing reduced fgfr4 mRNA expression and characterizing truncated Fgfr4 protein variants.

Key Points:

• FGFR4 knockout zebrafish exhibited normal development but homozygous mutants were significantly smaller than wildtype controls at three months post fertilization.
• The generated mutations resulted in truncated Fgfr4 proteins (215, 223, or 228 amino acids) compared to the full-length 922 amino acid protein.
• Reduced fgfr4 mRNA expression confirmed successful gene knockout in all generated mutant zebrafish strains.

Conclusions:

• The generated fgfr4 knockout zebrafish lines provide a valuable model for investigating FGFR4 signaling in vertebrate development.
• These zebrafish models can aid in understanding FGFR4's role in pediatric and adult cancers, and other associated diseases.
• The study highlights the potential of FGFR4 as a therapeutic target for various cancers.