title: A Pax3/Pax7-dependent population of skeletal muscle progenitor cells.
abstract: During vertebrate development, successive phases of embryonic and fetal myogenesis lead to the formation and growth of skeletal muscles. Although the origin and molecular regulation of the earliest embryonic muscle cells is well understood, less is known about later stages of myogenesis. We have identified a new cell population that expresses the transcription factors Pax3 and Pax7 (paired box proteins 3 and 7) but no skeletal-muscle-specific markers. These cells are maintained as a proliferating population in embryonic and fetal muscles of the trunk and limbs throughout development. Using a stable green fluorescent protein (GFP) reporter targeted to Pax3, we demonstrate that they constitute resident muscle progenitor cells that subsequently become myogenic and form skeletal muscle. Late in fetal development, these cells adopt a satellite cell position characteristic of progenitor cells in postnatal muscle. In the absence of both Pax3 and Pax7, further muscle development is arrested and only the early embryonic muscle of the myotome forms. Cells failing to express Pax3 or Pax7 die or assume a non-myogenic fate. We conclude that this resident Pax3/Pax7-dependent progenitor cell population constitutes a source of myogenic cells of prime importance for skeletal muscle formation, a finding also of potential value in the context of cell therapy for muscle disease.
authors.affiliation: C.N.R.S. URA 2578, Department of Developmental Biology, Pasteur Institute, 75724 Paris Cedex 15, France. frelaix@pasteur.fr
authors.forename: Frédéric
authors.initials: F
authors.lastname: Relaix
authors.forename: Didier
authors.initials: D
authors.lastname: Rocancourt
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mansouri
authors.forename: Margaret
authors.initials: M
authors.lastname: Buckingham
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology* / Q000196:embryology* / Q000378:metabolism; D000072041:PAX3 Transcription Factor; D051763:PAX7 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology / Q000378:metabolism; D019170:Somites / Q000166:cytology / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D000072041:PAX3 Transcription Factor; D051763:PAX7 Transcription Factor; D051761:Paired Box Transcription Factors; C497322:Pax7 protein, mouse; D012333:RNA, Messenger; D014157:Transcription Factors; C068686:Pax3 protein, mouse