Myogenin

Myogenin is a basic-helix-loop-helix (bHLH) transcription factor expressed during the development, maintenance, and repair of skeletal muscle. Myogenin belongs to the MyoD family of bHLH transcription factors, which also include MyoD, Myf5, and MRF4. In particular, it is a myogenic regulatory factor (MRF). When the DNA coding for myogenin was knocked out of the mouse genome, severe skeletal muscle defects were observed. Mice lacking both copies of myogenin (homozygous-null) suffer from perinatal lethality due to the lack of mature secondary skeletal muscle fibers throughout the body. somite -(myoD/myf5)--> myoblast -(myogenin/MRF4)--> myotube