Goldhamer, D.J., Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
Faerman, A., Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
Shani, M., Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
Emerson Jr., C.P., Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, United States

The molecular basis of skeletal muscle lineage determination was investigated by analyzing DNA control elements that regulate the myogenic determination gene myoD. A distal enhancer was identified that positively regulates expression of the human myoD gene. The myoD enhancer and promoter were active in myogenic and several nonmyogenic cell lines. In transgenic mouse embryos, however, the myoD enhancer and promoter together directed expression of a lacZ transgene specifically to the skeletal muscle lineage. These data suggest that during development myoD is regulated by mechanisms that restrict accessibility of mycD control elements to positive trans-acting factors.