title: Progenitors of skeletal muscle satellite cells express the muscle determination gene, MyoD.
abstract: Satellite cells are tissue-specific stem cells responsible for skeletal muscle growth and regeneration. Although satellite cells were identified almost 50 years ago, the identity of progenitor populations from which they derive remains controversial. We developed MyoD(iCre) knockin mice, and used Cre/lox lineage analysis to determine whether satellite cell progenitors express MyoD, a marker of myogenic commitment. Recombination status of satellite cells was determined by confocal microscopy of isolated muscle fibers and by electron microscopic observation of muscle tissue fixed immediately following isolation, using R26R-EYFP and R26R (beta-gal) reporter mice, respectively. We show that essentially all adult satellite cells associated with limb and body wall musculature, as well as the diaphragm and extraocular muscles, originate from MyoD+ progenitors. Neonatal satellite cells were Cre-recombined, but only a small minority exhibited ongoing Cre expression, indicating that most satellite cells had expressed MyoD prenatally. We also show that satellite cell development in MyoD-null mice is not due to functional compensation by MyoD non-expressing lineages. The results suggest that satellite cells are derived from committed myogenic progenitors, irrespective of the anatomical location, embryological origin, or physiological properties of associated musculature.
authors.affiliation: Department of Molecular and Cell Biology, Center for Regenerative Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Onur
authors.initials: O
authors.lastname: Kanisicak
authors.forename: Julio J
authors.initials: JJ
authors.lastname: Mendez
authors.forename: Shoko
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yamamoto
authors.forename: David J
authors.initials: DJ
authors.lastname: Goldhamer
mesh_terms: D000483:Alleles; D000818:Animals; D019070:Cell Lineage; D002469:Cell Separation; D018507:Gene Expression Regulation, Developmental; D055879:Gene Knock-In Techniques; D018390:Gene Targeting; D006614:Hindlimb / Q000166:cytology; D019426:Integrases / Q000378:metabolism; D051379:Mice; D009132:Muscles / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D017570:MyoD Protein / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D013194:Staining and Labeling; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D017570:MyoD Protein; C045073:Cre recombinase; D019426:Integrases