Pax7 Is Required for the Specification of Myogenic Satellite Cells

• Published in: Cell Vol. 102; no. 6; pp. 777 - 786
• Main Authors: Seale, Patrick, Sabourin, Luc A, Girgis-Gabardo, Adele, Mansouri, Ahmed, Gruss, Peter, Rudnicki, Michael A
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.09.2000
• Subjects: Age Factors; Animals; Cell Division - physiology; Cell Lineage - physiology; Cell Membrane - ultrastructure; Cell Nucleus - ultrastructure; Cells, Cultured; Flow Cytometry; Gene Expression Regulation, Developmental; Hematopoietic Stem Cells - chemistry; Hematopoietic Stem Cells - cytology; Homeodomain Proteins - analysis; Homeodomain Proteins - genetics; In Situ Hybridization; Mice; Mice, Inbred BALB C; Mice, Knockout; Microscopy, Electron; Muscle Fibers, Skeletal - chemistry; Muscle Fibers, Skeletal - cytology; Muscle, Skeletal - abnormalities; Muscle, Skeletal - chemistry; Muscle, Skeletal - ultrastructure; Pax7 gene; PAX7 Transcription Factor; RNA, Messenger - analysis
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/S0092-8674(00)00066-0

The paired box transcription factor Pax7 was isolated by representational difference analysis as a gene specifically expressed in cultured satellite cell-derived myoblasts. In situ hybridization revealed that Pax7 was also expressed in satellite cells residing in adult muscle. Cell culture and electron microscopic analysis revealed a complete absence of satellite cells in Pax7 −/− skeletal muscle. Surprisingly, fluorescence-activated cell sorting analysis indicated that the proportion of muscle-derived stem cells was unaffected. Importantly, stem cells from Pax7 −/− muscle displayed almost a 10-fold increase in their ability to form hematopoietic colonies. These results demonstrate that satellite cells and muscle-derived stem cells represent distinct cell populations. Together these studies suggest that induction of Pax7 in muscle-derived stem cells induces satellite cell specification by restricting alternate developmental programs.