Identification of responsive cells in the developing somite supports a role for beta-catenin-dependent Wnt signaling in maintaining the DML myogenic progenitor pool.
Somitic beta-catenin is involved in both maintaining a stem cell population and controlling myogenic differentiation. It is unclear how beta-catenin-dependent Wnt signaling accomplishes these disparate roles. The present study shows that only dorsal cells in the early somite respond to beta-catenin-dependent Wnt signaling and as the somites compartmentalize to form the dermomyotome and myotome, responding cells are detected primarily in the dorsomedial lip (DML). Forced activation of Wnt target genes in DML cells prevents their progeny from entering the myotome, while blocking activation allows myotomal entry. This suggests a role for beta-catenin-dependent/Wnt signaling in maintaining progenitor cells in the DML and that if beta-catenin-dependent/Wnt signaling is required to induce myogenesis, the response is transitory and rapidly down-regulated.
Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
Ian
I
Brauner
Douglas B
DB
Spicer
Catherine E
CE
Krull
Judith M
JM
Venuti
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002642:Chick Embryo; D018274:Electroporation; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D018613:Microscopy, Confocal; D024510:Muscle Development / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D019170:Somites / Q000166:cytology / Q000196:embryology*; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
D051153:Wnt Proteins; D051176:beta Catenin; D049452:Green Fluorescent Proteins