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The third wave of myotome colonization by mitotically competent progenitors: regulating the balance between differentiation and proliferation during muscle development
- Source :
- Development (Cambridge, England). 128(12)
- Publication Year :
- 2001
-
Abstract
- The myotome is formed by a first wave of pioneer cells originating from the entire dorsomedial region of epithelial somites and a second wave that derives from all four lips of the dermomyotome but generates myofibers from only the rostral and caudal edges. Because the precedent progenitors exit the cell cycle upon myotome colonization, subsequent waves must account for consecutive growth. In this study, double labeling with CM-DiI and BrdU revealed the appearance of a third wave of progenitors that enter the myotome as mitotically active cells from both rostral and caudal dermomyotome edges. These cells express the fibroblast growth factor (FGF) receptor FREK and treatment with FGF4 promotes their proliferation and redistribution towards the center of the myotome. Yet, they are negative for MyoD, Myf5 and FGF4, which are, however, expressed in myofibers.The proliferating progenitors first appear around the 30-somite stage in cervical-level myotomes and their number continuously increases, making up 85% of total muscle nuclei by embryonic day (E)4. By this stage, generation of second-wave myofibers, which also enter from the extreme lips is still under way. Formation of the latter fibers peaks at 30 somites and progressively decreases with age until E4. Thus, cells in these dermomyotome lips generate simultaneously distinct types of muscle progenitors in changing proportions as a function of age. Consistent with a heterogeneity in the cellular composition of the extreme lips, MyoD is normally expressed in only a subset of these epithelial cells. Treatment with Sonic hedgehog drives most of them to become MyoD positive and then to become myofibers, with a concurrent reduction in the proportion of proliferating muscle precursors.
- Subjects :
- Time Factors
Muscle Fibers, Skeletal
Fibroblast Growth Factor 4
Dermomyotome
Gene Expression
Mitosis
Coturnix
Biology
MyoD
Fibroblast growth factor
Myotome
Proto-Oncogene Proteins
FGF4
medicine
Animals
Hedgehog Proteins
Receptor, Fibroblast Growth Factor, Type 4
Sonic hedgehog
Molecular Biology
MyoD Protein
Muscles
Stem Cells
Receptor Protein-Tyrosine Kinases
Cell Differentiation
Anatomy
Embryonic stem cell
Receptors, Fibroblast Growth Factor
Cell biology
Fibroblast Growth Factors
medicine.anatomical_structure
biology.protein
Trans-Activators
MYF5
Cell Division
Developmental Biology
Subjects
Details
- ISSN :
- 09501991
- Volume :
- 128
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- Development (Cambridge, England)
- Accession number :
- edsair.doi.dedup.....a239c375e7ce5227fb9182103399912e