Swimming toward solutions: Using fish and frogs as models for understanding RASopathies

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• The RAS signaling pathway is crucial for cell growth, survival, and differentiation.
• Dysregulation of the RAS pathway leads to RASopathies, a group of human developmental syndromes.
• Key patient symptoms include congenital heart disease, craniofacial anomalies, and neurocognitive delay.

Purpose of the Study:

• To discuss the utility of aquatic model systems (zebrafish and Xenopus) for studying RASopathies.
• To highlight how these models recapitulate core symptoms observed in human patients.
• To explore the relationship between RAS pathway activation strength and disease presentation.

Main Methods:

• Expression of disease-associated RAS mutations in zebrafish and Xenopus embryos.
• Observation and quantitative assaying of developmental phenotypes, including craniofacial and cardiac defects.
• Analysis of embryonic elongation as a readout of mutation strength.

Main Results:

• Aquatic models display dysmorphic craniofacial structures (e.g., wider heads) and cardiac development delays.
• Embryonic elongation due to convergence and extension defects serves as a quantifiable measure of mutation impact.
• Evidence suggests both hyperactivity and attenuation of RAS signaling may contribute to disease etiology.

Conclusions:

• Zebrafish and Xenopus are advantageous model systems for investigating RASopathies due to conserved pathways.
• These models offer insights into the complex interplay between RAS mutation strength and disease manifestation.
• A standardized approach for characterizing these models is proposed to facilitate comparative studies and enhance understanding.