A model for the modulation of muscle cell determination and differentiation by growth factors.

In an adult organism three principal types of muscle tissue can be found: skeletal, smooth, and cardiac. While each display subtle differences, for the most part they express a common set of genes that are representative of differentiated muscle. Several in vitro muscle cell lines have provided clues as to how the developmental programs of muscle cell proliferation, determination, and differentiation are controlled. In this paper we will explore recent advances in our understanding of how growth factors, acting through specific signal transduction pathways, control muscle gene expression. The transcription of muscle genes is controlled by specific cis-acting regulatory sequences. We will discuss how growth factors may exert their effects on muscle genes by modulating the expression of nuclear DNA-binding proteins that directly regulate muscle gene expression.