Dystrophin expression during skeletal myogenesis

The factors that regulate dystrophin accumulation, and its association with other proteins in culture, are largely unknown. In this study I have examined the effects of chemical agents on dystrophin accumulation in culture, as well as determined whether dystrophin in culture has associations with glycoproteins in a similar fashion to that found in normal muscle tissue. My results show that the onset of detectable dystrophin accumulation occurs shortly after myoblast fusion has taken place, and increases rapidly thereafter as a percentage of total cell protein. The effects of depolarizing concentrations of potassium ion, resulting in the inhibition of myotube contraction, are negligible, consistent with the fact that dystrophin is a cytoskeletal protein. I have found that 5-bromo-2$ sp prime$-deoxyuridine, known to affect terminal differentiation in myoblasts, markedly inhibits dystrophin accumulation in culture. Finally, I have found that dystrophin in cultured cells associates with Wheat Germ Agglutinin-binding proteins, as reported for adult skeletal muscle tissue, implying that the expression of these glycoproteins either precedes or occurs coordinately with dystrophin expression in culture