Myf-5(m1)/Myf-6(m1) compound heterozygous mouse mutants down-regulate Myf-5 expression and exert rib defects: evidence for long-range cis effects on Myf-5 transcription

Dev Biol. 1996 Feb 25;174(1):140-7. doi: 10.1006/dbio.1996.0058.


Myf-6 and Myf-5, two members of the family of muscle-specific regulatory genes, are located less than 10 kb apart in the mouse and human genomes. We have shown recently that homozygous mutant mice carrying a pgk-neo-cassette in the first exon of the Myf-6 gene display minor alterations of skeletal musculature but develop a severe rib defect, most likely due to a drastic down-regulation of Myf-5 expression. The mechanism by which the Myf-6 mutation affects the Myf-5 gene is unknown. In order to determine whether Myf-5 transcription is inhibited by the Myf-6 mutation in cis or in trans, we generated compound heterozygous mice carrying inactivated Myf-5 and Myf-6 alleles on different chromosomes. Here, we demonstrate that double-heterozygous mutants exhibit truncated ribs and severe depression of Myf-5 transcription, a phenotype similar to the previously described homozygous Myf-6 mutant mice. These results indicate that the Myf-6 mutation inhibits Myf-5 gene expression by a long-range cis effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA-Binding Proteins*
  • Gene Expression Regulation, Developmental
  • Heterozygote
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Muscle Proteins / physiology*
  • Myogenic Regulatory Factor 5
  • Myogenic Regulatory Factors / physiology*
  • RNA, Messenger / genetics
  • Ribs / embryology*
  • Trans-Activators*
  • Transcription, Genetic


  • DNA-Binding Proteins
  • Muscle Proteins
  • Myf5 protein, mouse
  • Myogenic Regulatory Factor 5
  • Myogenic Regulatory Factors
  • RNA, Messenger
  • Trans-Activators
  • myogenic factor 6