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In Vivo Modeling of the Morbid Human Genome using Danio rerio
Published on: August 24, 2013
In vivo characterization of mutant myotilins
Etsuko Keduka1, Yukiko K Hayashi, Sherine Shalaby
1Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Abstract:
Myofibrillar myopathy (MFM) is a group of disorders that are pathologically defined by the disorganization of the myofibrillar alignment associated with the intracellular accumulation of Z-disk-associated proteins. MFM is caused by mutations in genes encoding Z-disk-associated proteins, including myotilin. Although a number of MFM mutations have been identified, it has been difficult to elucidate the precise roles of the mutant proteins. Here, we present a useful method for the characterization of mutant proteins associated with MFM. Expression of mutant myotilins in mouse tibialis anterior muscle by in vivo electroporation recapitulated both the pathological changes and the biochemical characteristics observed in patients with myotilinopathy. In mutant myotilin-expressing muscle fibers, myotilin aggregates and is costained with polyubiquitin, and Z-disk-associated proteins and myofibrillar disorganization were commonly seen. In addition, the expressed S60C mutant myotilin protein displayed marked detergent insolubility in electroporated mouse muscle, similar to that observed in human MFM muscle with the same mutation. Thus, in vivo electroporation can be a useful method for evaluating the pathogenicity of mutations identified in MFM.
Insights
Researchers developed an in vivo electroporation method to study myofibrillar myopathy (MFM). This technique effectively models MFM pathology in mice, aiding the characterization of mutant proteins and their disease mechanisms.
Area of Science:
- Muscle biology
- Molecular genetics
- Pathology
Background:
- Myofibrillar myopathy (MFM) is characterized by myofibrillar disorganization and Z-disk protein accumulation.
- Mutations in genes like myotilin cause MFM, but understanding mutant protein function is challenging.
Purpose of the Study:
- To develop and validate a novel in vivo method for characterizing MFM-associated mutant proteins.
- To assess the pathogenicity of myotilin mutations using this new technique.
Main Methods:
- In vivo electroporation was used to express mutant myotilins in mouse tibialis anterior muscle.
- Pathological and biochemical analyses were performed on electroporated muscle tissues.
- Detergent insolubility of mutant myotilin was assessed.
Main Results:
- In vivo electroporation successfully recapitulated MFM pathological changes in mouse muscle.
- Mutant myotilin formed aggregates, co-stained with polyubiquitin, and led to myofibrillar disorganization.
- The S60C mutant myotilin exhibited detergent insolubility, mirroring findings in human MFM.
Conclusions:
- In vivo electroporation is a valuable tool for evaluating the pathogenicity of MFM-related mutations.
- This method aids in understanding the molecular mechanisms underlying myotilinopathies.
