Electrotransfer in differentiated myotubes: a novel, efficient procedure for functional gene transfer

Area of Science:

• Cell Biology
• Molecular Biology
• Physiology

Background:

• Efficient gene transfer into multinucleated skeletal muscle fibers is crucial for studying muscle physiology and disease.
• Current methods, primarily viral vectors, have limitations for experimental manipulation in terminally differentiated myotubes.

Purpose of the Study:

• To develop and validate a novel in vitro method for efficient gene transfer into differentiated myotubes.
• To compare the efficiency of this new method against standard transfection techniques.
• To demonstrate the utility of this method for functional studies by transfecting a dominant-negative mutant.

Main Methods:

• Development of an in vitro electroporation protocol for naked DNA transfer into differentiated myotubes cultured on coverslips.
• Quantitative assessment of gene transfer efficiency using luciferase reporter gene assays.
• Functional validation through transfection of a dominant-negative ADP-ribosylation factor 1 (ARF1) mutant (ARF1N126I) and co-transfection with beta-galactosidase.

Main Results:

• Electroporation achieved at least 1000-fold higher efficiency compared to standard transfection methods.
• Approximately 45% of myotubes were successfully transfected using the electroporation protocol.
• Transfection of ARF1N126I mutant altered endoplasmic reticulum-Golgi traffic and inhibited myoblast fusion, confirming functional gene transfer.

Conclusions:

• Electroporation is a highly efficient and reliable method for gene transfer in terminally differentiated skeletal muscle myotubes.
• This technique overcomes limitations of viral vectors and provides a powerful tool for molecular studies in muscle.
• The successful functional manipulation of cellular processes demonstrates the broad applicability of electroporation in muscle research.