Isolation and characterization of human myogenic factors involved in lineage determination and regulation of gene expression

We review the isolation and characterization of a group of myogenic determination factors which are exclusively expressed in human skeletal muscle tissues. These Myf clones have been identified by taking advantage of their moderate cross hybridization to mouse MyoD1 cDNA and to each other. Expression of individual Myf clones under the control of a constitutive viral promoter, indistinguishably initiates the myogenic program in 10T1/2 fibroblasts. The expression of a single Myf protein can activate the transcription of its own gene and that of other members of the Myf gene family. These observations suggest that initiation and maintenance of the muscle phenotype may involve several myogenic determination genes which individually or in combination act in a yet undefined hierarchy or network.