Immunofluorescence studies on amphibian myoblast differentiation.

Differentiating myoblasts from urodele amphibians were cultivated in vitro and treated by immunofluorescence techniques and (or) inhibitors of RNA and protein syntheses. These experiments lead to the conclusion that the differentiation of these cells is directed by long-lived m-RNAs which are already present in morphologically undifferentiated cells and may act for at least 6 days. Contrary to observations on cultivated myogenic cells from other groups, the fusion of urodele myoblasts is not a prerequisite for a normal and functional differentiation (contractions) since isolated myoblasts differentiate quite normally. The appearance and further evolution of myosin and actin occur synchronously in this biological system.