Cardiac and skeletal myopathy in beta myosin heavy-chain simian virus 40 tsA58 transgenic mice

Area of Science:

• Cardiovascular Biology
• Developmental Biology
• Molecular Genetics

Background:

• Mechanisms of cardiac muscle differentiation and development are not fully understood.
• Investigating the interplay between cardiocyte proliferation and differentiation is crucial for understanding heart development.

Purpose of the Study:

• To examine the relationship between cardiocyte proliferation and differentiation.
• To assess the efficacy of the rat beta myosin heavy-chain (MHC beta) gene promoter in targeting gene expression during mouse development.

Main Methods:

• Utilized a transgenic mouse model.
• Employed a fragment of the rat MHC beta gene to direct the expression of a thermolabile simian virus 40 large tumor antigen allele (tsA58).
• Monitored transgene expression and developmental regulation in the heart and skeletal muscle.

Main Results:

• Transgene expression was detected in the developing heart as early as 10 days postconception.
• Gene expression was developmentally regulated, mirroring the endogenous MHC beta gene.
• Cardiac and skeletal myopathies developed in a subset of transgenic mice, despite the temperature-sensitive nature of the viral protein.

Conclusions:

• The MHC beta gene promoter can target gene expression in the developing heart and skeletal muscle.
• Aberrant expression of the viral oncogene, even in a temperature-sensitive manner, can lead to cardiac and skeletal myopathies.
• This model provides a tool to study the genetic regulation of cardiogenesis and associated pathologies.