title: Study of muscle cell dedifferentiation after skeletal muscle injury of mice with a Cre-Lox system.
abstract: BACKGROUND
  Dedifferentiation of muscle cells in the tissue of mammals has yet to be observed. One of the challenges facing the study of skeletal muscle cell dedifferentiation is the availability of a reliable model that can confidentially distinguish differentiated cell populations of myotubes and non-fused mononuclear cells, including stem cells that can coexist within the population of cells being studied.
  
  
  RESULTS
  In the current study, we created a Cre/Lox-β-galactosidase system, which can specifically tag differentiated multinuclear myotubes and myotube-generated mononuclear cells based on the activation of the marker gene, β-galactosidase. By using this system in an adult mouse model, we found that β-galactosidase positive mononuclear cells were generated from β-galactosidase positive multinuclear myofibers upon muscle injury. We also demonstrated that these mononuclear cells can develop into a variety of different muscle cell lineages, i.e., myoblasts, satellite cells, and muscle derived stem cells.
  
  
  CONCLUSIONS
  These novel findings demonstrated, for the first time, that cellular dedifferentiation of skeletal muscle cells actually occurs in mammalian skeletal muscle following traumatic injury in vivo.
authors.affiliation: The Laboratory of Molecular Pathology, Stem Cell Research Center (SCRC), Children's Hospital of UPMC, Pittsburgh, Pennsylvania, USA.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Mu
authors.forename: Hairong
authors.initials: H
authors.lastname: Peng
authors.forename: Haiying
authors.initials: H
authors.lastname: Pan
authors.forename: Johnny
authors.initials: J
authors.lastname: Huard
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D054337:Cell Dedifferentiation / Q000235:genetics / Q000502:physiology*; D058948:Cell Tracking / Q000379:methods; D019426:Integrases / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008822:Mice, Transgenic; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D009928:Organ Specificity / Q000235:genetics; D012038:Regeneration / Q000502:physiology; D019076:Transgenes / Q000502:physiology; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: C045073:Cre recombinase; D019426:Integrases; D001616:beta-Galactosidase