MUSCLE DEFICIENCY AND NEONATAL DEATH IN MICE WITH A TARGETED MUTATIONIN THE MYOGENIN GENE

Myogenin is a muscle-specific transcription factor that can induce myo genesis in a variety of cell types in tissue culture. To test myogenin 's role in vivo, mice homozygous for a targeted mutation in the myogen in gene were generated. These mice survive fetal development but die i mmediately after birth and show a severe reduction of all skeletal mus cle. Myogenin-mutant mice differ from mice carrying mutations in genes for the related myogenic factors Myf5 and MyoD, which have no muscle defects. Myogenin is therefore essential for the development of functi onal skeletal muscle.