Preparing your results

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Targeted inactivation of the muscle regulatory gene Myf-5 results in abnormal rib development and perinatal death.

The Myf-5 gene, a member of the myogenic basic HLH factor family, has been inactivated in mice after homologous recombination in ES cells. Mice lacking Myf-5 were unable to breathe and died immediately after birth, owing to the absence of the major distal part of the ribs. Other skeletal abnormalities, except for complete ossification of the sternum, were not apparent. Histological examination of skeletal muscle from newborn mice revealed no morphological abnormalities. Northern blot analysis demonstrated normal levels of muscle-specific mRNAs including MyoD, myogenin, and Myf-6. However, the appearance of myotomal cells in early somites was delayed by several days. These results suggest that while Myf-5 plays a crucial role in the formation of lateral sclerotome derivatives, Myf-5 is dispensable for the development of skeletal muscle, perhaps because other members of the myogenic HLH family substitute for Myf-5 activity.

Pubmed ID: 1423602


  • Braun T
  • Rudnicki MA
  • Arnold HH
  • Jaenisch R



Publication Data

October 30, 1992

Associated Grants

  • Agency: NCI NIH HHS, Id: R35 CA 44339-05

Mesh Terms

  • Animals
  • Animals, Newborn
  • Chimera
  • DNA-Binding Proteins
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Muscle Proteins
  • Muscles
  • Myogenic Regulatory Factor 5
  • Perinatology
  • Respiratory Insufficiency
  • Ribs
  • Trans-Activators