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Updated: Jul 11, 2025
Analysis of Embryonic and Larval Zebrafish Skeletal Myofibers from Dissociated Preparations
Published on: November 13, 2013
Two zebrafish cacna1s loss-of-function variants provide models of mild and severe CACNA1S-related myopathy
Yukari Endo1, Linda Groom2, Sabrina M Wang1
1Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada.
Abstract:
CACNA1S-related myopathy, due to pathogenic variants in the CACNA1S gene, is a recently described congenital muscle disease. Disease associated variants result in loss of gene expression and/or reduction of Cav1.1 protein stability. There is an incomplete understanding of the underlying disease pathomechanisms and no effective therapies are currently available. A barrier to the study of this myopathy is the lack of a suitable animal model that phenocopies key aspects of the disease. To address this barrier, we generated knockouts of the two zebrafish CACNA1S paralogs, cacna1sa and cacna1sb. Double knockout fish exhibit severe weakness and early death, and are characterized by the absence of Cav1.1 α1 subunit expression, abnormal triad structure, and impaired excitation-contraction coupling, thus mirroring the severe form of human CACNA1S-related myopathy. A double mutant (cacna1sa homozygous, cacna1sb heterozygote) exhibits normal development, but displays reduced body size, abnormal facial structure, and cores on muscle pathologic examination, thus phenocopying the mild form of human CACNA1S-related myopathy. In summary, we generated and characterized the first cacna1s zebrafish loss-of-function mutants, and show them to be faithful models of severe and mild forms of human CACNA1S-related myopathy suitable for future mechanistic studies and therapy development.
Insights
Researchers developed zebrafish models for CACNA1S-related myopathy by creating cacna1s gene knockouts. These models faithfully replicate both severe and mild forms of the human congenital muscle disease, aiding future research.
Area of Science:
- Genetics
- Molecular Biology
- Zebrafish Models
Background:
- CACNA1S-related myopathy is a congenital muscle disease caused by pathogenic variants in the CACNA1S gene.
- Disease mechanisms and effective therapies remain poorly understood.
- A lack of suitable animal models hinders research.
Purpose of the Study:
- To generate and characterize zebrafish loss-of-function mutants for CACNA1S paralogs.
- To establish faithful animal models for studying CACNA1S-related myopathy.
Main Methods:
- Generated double knockout zebrafish for CACNA1S paralogs (cacna1sa and cacna1sb).
- Phenotypically characterized homozygous and heterozygous mutants.
- Assessed Cav1.1 expression, muscle structure, and excitation-contraction coupling.
Main Results:
- Double knockout fish exhibited severe weakness, early death, absent Cav1.1 expression, abnormal muscle structure, and impaired excitation-contraction coupling, mirroring severe human disease.
- A double mutant (cacna1sa homozygous, cacna1sb heterozygote) showed normal development but displayed reduced body size, facial abnormalities, and muscle cores, phenocopying mild human disease.
Conclusions:
- The first cacna1s zebrafish loss-of-function mutants were successfully generated and characterized.
- These zebrafish models accurately represent both severe and mild forms of human CACNA1S-related myopathy.
- The models are suitable for future mechanistic studies and the development of novel therapies.
