Fibroblast growth factor and transforming growth factor beta repress transcription of the myogenic regulatory gene MyoD1

In this report, we demonstrate that myogenic cultures inhibited from differentiating by treatment with fibroblast growth factor or transforming growth factor beta show reduced levels of MyoD1 mRNA. Although this repression may contribute to the inhibition of myogenesis by growth factors, additional regulatory pathways must be affected, since inhibition still occurs in cultures engineered to constitutively express MyoD1 mRNA.