FIG. 1.

Postmitotic expression of IGF-I enhances expression of the markers of muscle terminal differentiation. Control L6E9 myoblasts and L6E9 myoblasts stably transfected with the MLC–IGF-I expression vector (L6MLC/IGF-I) were grown to approximately 80% confluence in GM and then switched to DM (day 0). Total RNA was isolated from proliferative myoblasts (lanes GM) and at 0, 1, 2, 3, and 4 days after switching to DM. Northern blots of total RNA samples (15 μg) were analyzed with the indicated ³²P-labeled probes. Ethidium bromide (EtBr) staining was used to verify equal loading of the RNA sample.