title: Identification of skeletal muscle precursor cells in vivo by use of MyoD1 and myogenin probes.
abstract: The activation of mononuclear muscle precursor cells after crush injury to mouse tibialis anterior muscles was monitored in vivo by in situ hybridization with MyoD1 and myogenin probes. These genes are early markers of skeletal muscle differentiation and have been extensively studied in vitro. The role in vivo of these regulatory proteins during myogenesis of mature muscle has not been studied previously. MyoD1 and myogenin mRNA were present in occasional mononuclear cells of uninjured muscle. Increased MyoD1 and myogenin mRNA sequences in mononuclear cells were detected as early as 6 h after injury, peaked between 24 and 48 h, and thereafter declined to pre-injury levels at about 8 days. The mRNAs were detected in mononuclear cells throughout the muscle, with the majority of cells located some distance from the site of crush injury. The presence of MyoD1 and myogenin mRNA at 6 to 48 h indicates that transcription of these genes is occurring at the same time as replication of muscle precursor cells in vivo. At no time were significant levels of mRNA for these genes detected in myotubes. MyoD1 and myogenin provide precise markers for the very early identification and study of mononuclear skeletal muscle precursor cells in muscle regenerating in vivo.
authors.affiliation: Department of Pathology, Queen Elizabeth II Medical Centre, University of Western Australia, Nedlands.
authors.forename: M D
authors.initials: MD
authors.lastname: Grounds
authors.forename: K L
authors.initials: KL
authors.lastname: Garrett
authors.forename: M C
authors.initials: MC
authors.lastname: Lai
authors.forename: W E
authors.initials: WE
authors.lastname: Wright
authors.forename: M W
authors.initials: MW
authors.lastname: Beilharz
mesh_terms: D000818:Animals; D015415:Biomarkers; D008297:Male; D051379:Mice; D015335:Molecular Probes; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000166:cytology* / Q000293:injuries / Q000378:metabolism; D017570:MyoD Protein; D018008:Myogenin; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D015335:Molecular Probes; D009124:Muscle Proteins; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; C503801:Myog protein, mouse; D018008:Myogenin; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger