抄録
The effects of calcium and temperature on fusion of quail embryonic myoblasts were examined using cells transformed with a temperature-sensitive mutant of Rous sarcoma virus (ts-RSV). The transformed quail myoblasts (QM-RSV)fused to form myotubes at 41°C, the non-permissive temperature, but not at 35.5°C, the permissive temperature. On incubation at 41°C, a period of more than 10 hr was needed for the myoblasts to become fusion-competent, but calcium was not needed for development of fusion-competence. Once the cells had become competent, fusion proceeded even at 35.5°C. These results suggest that the src gene product expressed at 35.5°C may control the fusion of cells in the competent stage by inactivating a components) that is associated with fusion-competence. However, fusion of even myoblasts in the competent stage was blocked in calcium-deficient medium, suggesting that calcium is essential for the fusion, probably at a step immediately before membrane union. Unlike fusion, other biochemical processes of differentiation proceeded even in calcium-deficient medium, indicating a distinction of fusion from these other processes during myoblast differentiation.
